FAQs about Marine Crab Compatibility, Removal
Strategies... 3
Related Articles: Crabs, Hermit
Crabs,
Related FAQs: Marine Crab Compatibility 1,
Marine Crab Compatibility 2, Marine Crabs 1, Marine Crabs 2,
Marine Crabs 3, Marine Crabs 4, Marine Crab Identification, Crab Behavior,
Marine Crab Selection, Marine Crab
Systems, Marine Crab Feeding,
Marine Crab Reproduction,
Marine Crab Disease, Micro-Crustaceans, Amphipods, Copepods, Mysids, Hermit Crabs, Shrimps,
Cleaner Shrimps, Banded Coral Shrimp, Mantis Shrimp, Anemone
Eating Shrimp,
Crustacean Identification,
Crustacean Selection, Crustacean Behavior,
Crustacean Compatibility, Crustacean
Systems, Crustacean Feeding,
Crustacean Disease, Crustacean Reproduction,
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Crab ID 2/2/19
Good Morning,
<Morning, Jason>
I have written to you recently about a stocking list for my 75g and asked for a
snail I'd and now I'm asking about a crab id. I know crabs in general can't be
trusted but am wondering the potential size of the crab and if it is more safe
or less safe than most crabs.
<Certainly they can´t be trusted, especially as they grow>
The live sand and rock came from the Tampa Bay Area. I've seen about 6 or so in
the tank ranging from a quarter inch to about 1 inch and they look like the same
species. I did try trapping with some mysis in a glass but all I caught were
some Nassarius snails but no crabs. If it helps the tips of the claws are black
with spots on the body and a flattish head.
<Well, the crab on your image appears to be some species form Menippidae family,
probably Menippe mercenaria; they can grow to 7 inches. I wouldn´t trust it but
if you still want to keep it, watch its behavior closely, particularly if you
have small fish. >
Thanks Jason
<Cheers. Wil .>
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Re: Crab ID 2/2/19
Thanks Wil for the reply and I think you may be right. I don't trust them and
would like to catch them but may be difficult since they are not falling for the
crab trap and the snails get all the food. Right now there are no fish in the
tank but will be putting in a shrimp/goby pair, Dartfish, Jawfish, and fairy
wrasse. Maybe I'll try a mediumish wrasse that may go after the crabs that I
could move at a later date.
<Good idea about the medium size wrasse, or, since there´s no fish in
the tank yet…. you could borrow a triggerfish from a friend or LFS; and it will
eat the crab if left hungry for a few days. >
Thanks Jason
<Glad to help, Jason. Wil. >
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Shrimp and crab compatibility 5/29/17
Hey guys!
<Carter>
I have a 45 gallon mixed (lps/softies) with about 45 pounds of rock. It
currently houses various snails, hermits, a fire shrimp (Lysmata
debelius), a blue porcelain crab (Petrolisthes spp) and several fish.
Three of those fish are potential "shrimpivores and crabivores"...a
redlined wrasse, a carpenters fairy wrasse, and an orchid Dottyback. Is
there an appropriate species of shrimp that you would chance adding to
the tank, and would it be appropriate to add an emerald crab or two?
<Mmm; well; given plenty of hidey holes (for molting, soft-bodied
periods); most any of the larger shrimps would/could go here. I'd have
you read here:
http://www.wetwebmedia.com/HighInvertInd.htm
scroll down to the "Shrimp" tray; read at the family level. I'd avoid
Stenopids and am not a fan of Mithraculus... as you'll see by reading re
them on this same page>
Thanks so much for always being there!
Carter
<Welcome. Bob Fenner>
Possible Xanthid Crab? 5/22/16
Good evening Bob and Company!
<Hey Suse!>
Thank you so much for your fabulous website; you are an amazing resource.
<Glad to share>
I keep a 60 gallon seahorse and soft coral reef (primarily sun corals and
assorted sea fans) and always acquire all of my livestock (aside from the
seahorses, which come directly from the breeder) from a single local shop that I
trust.
<Okay!>
Tonight I brought home a piece of live rock with mixed colonies of clove and
daisy polyps (it’s lovely) - but about an hour after introducing it to the tank,
I noticed it “breathing” - which, of course, neither of these species do. A
brief investigation with a flashlight and a pair of long tweezers revealed this
little guy hiding beneath the polyps. (Photos attached.)
<I see this Decapod>
His legs are much hairier than they appear in the photos - like the legs of a
Mithrax crab (but his pincers are clearly wrong for Mithrax).
<Yes>
I pulled the rock from the tank at once, nudged the crab into a bowl, and shot
these photos. After spending about an hour on your site, I suspect he’s a
Xanthid - and that it’s a good thing I removed him before he could cause any
havoc. Can you confirm his species, or at least let me know if I should keep him
away from the seahorse reef?
<It is a member of this family; and I would keep it out of your seahorse system>
(My husband thinks he’s cute, but I don’t think my softies and seahorses will
appreciate this particular variety of cuteness.)
<Mmm; if you have a live sump; I might place this crab there; where it can do no
harm>
Thank you for all you do!
Susan
<Certainly welcome. Thank you for sharing. Bob Fenner>
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Duncan coral flash damage... flesh? Decapods
5/1/16
Hi first I would like to say thank you for the great information that
you provide, I am new to saltwater and all that goes with it and I get a
wealth of information from you.
<Thanks from the crew.>
I have two emerald crabs that are feasting on my corals
I have tried feeding them more so they will not munch on the coral but
their appetites seem endless so with that said I have caught them and
they are jailed in my tank until my LFS opens today in which they will
be returned and hopefully sold to someone that can appreciate them for
what they are.
<Crabs in general are opportunistic little beasts who will go
for almost anything they can (shred) and fit into their mouths.
That said they are fascinating in their own right and worthwhile. Just
be sure you know what you are getting into, but certain kinds have
particular uses as anti-algae weapons vs. "bubble" algae and so on, as
you will no doubt have read on WWM. Generally untrustworthy however.)
The emeralds have eaten a good bit of flesh off the base of my Duncan
coral, will the flesh grow back?
<A healthy colony should have little trouble recovering from
non-catastrophic damage. They are surprisingly resilient although there
are no guarantees. I wouldn't lose sleep.>
should I dip it in coral RX or Iodine mix to prevent infection or should
I just leave it alone and see what happens. Thank you again for the
great service that you provide.
Tonya
<I'd watch it, leave it alone, and see how it progresses before moving
onto disruptive treatments. If it seems to be going downhill (melting,
discoloration) then the dip might be worth looking into. A "wait and
see" approach would be my approach...should recover fine, just monitor
it, keep things clean in the system, keep it fed. Some target-fed meaty
foods will be appreciated. -Earl>
Is this crab ok for reef tank
1/24/16
I'm just new to the hobby, I live in Scotland, I have just set up my tank about
2 months only have
Clean up crew of snails and hermits and a few soft corals , this guy obviously
hitch hiked on my live rock, he doesn't move all day and only when it's pitch
black .
<Ah yes; looks to be a Xanthid (member of that family of crabs); not
"very" safe... I personally would remove, or at least isolate (in a sump; an
enclosed area...) away from your corals, fishes. May sample in time.
Bob Fenner>
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Live rock and dreaded hitchhiker crabs; comp./control
4/29/13
Hi folks!!!!! Loving all the forums, and your help and suggestions for
my specific questions have been invaluable!
But, here goes: 29 BioCube, parameters good, 20 pounds of live rock.
Livestock is: two Percularis clowns, one Banggai Cardinal, and a
Fireshrimp.
Unfortunately though the live rock came with its fair share of
hitchhikers.
We thought we had gotten all crabs out, but to my horror found two more
today. We pulled the chunk out, and attempted to do away with the
intruders. Traps never worked,
<Try other traps, baits>
and we always had to resort to poking them with a coat hanger.
Well, this time we had to take drastic measures and freshwater dip the
chunk of rock. And instead of two crabs, we came away with six!!!!!! The
rock was only in the water for about 30 seconds. And we took saltwater
from our tank and let it soak afterward. We did away with the saltwater
it soaked in once we were finished and had cleaned our tank up a bit.
Now comes the part where you folks chastise me and tell me how many
things I did wrong!!! Everyone in the tank seems fine, still doing their
fishy/shrimpy thing. Should I expect something bad to happen in the next
few hours?!! Help!!!!!
<You're doing fine. Not to worry. Bob Fenner>
Crab ID please; comp. f' 4/23/13
I think I have the same crab as a previous request for ID who sent a
photo.
Here is a copy of the request.
Reef Aquarium Hitchhiker Crab ID Needed? 9/26/08
Hello, I wondered if you could identify this crab?
Thank you in advance~
<Mmm, I can't seem to find in my ref.s... Can you wait a till 10/6 or
so?
Will ask LynnZ to look at. BobF>
I hope it is ok to do this.
<<Ah yes; referring to others work (in this case a photo) is fine>>
The crab came with a new piece of live rock and stays in a crevice usually
only waving a claw out to pick things of the rock. I have, however seen
it just out a couple of times but only for a matter of seconds and no
time to take a photo. It is very similar to the picture above. It has
faintly striped legs like a Pom Pom, a dark oval carapace which is about
10 mm across and has markedly unequal claw size which are quite long for
the size of the crab. It has a delicate claw with a thin arm and a much
more heavily built one, again, very similar to above. I would be glad to
know if I can leave it in my small 30 L Nano tank as it will be very
difficult to catch.
<<I would likely leave it there for now... All decapods/true crabs are
opportunistic, will try to eat other animals; but this one is small, may
stay small, not pose a problem. If trouble, it can be baited/removed
later>>
Nevertheless, I do not want it to damage my barnacle blenny (he's quite
tough) or my blue stripe pipe fish who keeps sticking his head in its
lair.
Any advice would be greatly appreciated.
<<You have it. T'were it me/mine, I'd hold off on removal at least for
now.
Bob Fenner>>
Re: Crab ID please, another lifted pic
4/26/13
Hi Bob Fenner,
Thanks for your reply and I will follow your advice. I think I have
tracked it down as Tanaocheles bidentata on an obscure online
classification book which happened to include a photo
<I see this>
This is identical as far as I can see but info for it, on the net, is
very scarce with nothing more than its taxonomy classification. I was
hoping to find out something about its habits and its likely fully grown
size. If you have any info on this crab I would be interested to hear.
Thanks again for your help and great website.
Regards
Max
<I do not; but thank you. BobF>
Malevolent Crab? 4/2/13
Dear crew
<Hello, Lynn here today.>
I have a few of these crabs in my reef tank and don’t know if they are
the kind I should have in there or not.
<The short answer is no, since, at least the one photographed, is a
“true” crab (brachyuran: two claws + 4 pairs of walking legs) as opposed
to a porcelain/”false” crab (Anomuran, family Porcellanidae: 2
claws + 3 pairs of walking legs). Brachyurans can have leanings
towards various foods but they’re opportunistic omnivores that will eat
just about anything when hungry and/or given half a chance.
The longer answer involves examining the claws in order to get a better
idea of a crab’s main diet. Judging from what I see in the photo,
your crab most likely has spoon/spatulate-shaped claw tips. It’s
believed that these are useful for scraping algae, etc., off hard
surfaces, grasping filamentous algae, and/or scooping up soft materials
(e.g. detritus and/or coral mucus). It would be nice if these claw
tips were indicative of a single family or genus, but they are found in
many. These crabs tend to be a bit better risk in reef tanks than
say, a large, heavy-clawed Xanthid, or a more slender, sharp-clawed
Portunid (swimming crab), but by no means does this make them “safe”.
They're still opportunistic omnivores that may be fairly well-behaved
when small and well fed, but can be a problem later on as their bodies
and appetites grow, and competition for food increases.>
I did not purchase them. I guess they would be around 6 years old.
<I can’t tell how large the one is in the photo, but even if the crabs
you have are a smaller species, they are still capable of damaging
livestock.>
They only come out at night. I've lost a few small fish and can't
seem to keep any shrimp around. I figured maybe these crabs are
the reason why.
<That could be part of it, especially if the crabs are able to grab a
shrimp when it's vulnerable during a molt.>
Any thoughts?
<Yes, if possible, I would trap/capture the crabs and find them a new
home in a sump or elsewhere. Please see WWM regarding crab removal (3
pages, starting here:
http://www.wetwebmedia.com/swcrabcomp.htm >
Thank You
<You’re most welcome.>
L. Splitter
<Take care, Lynn Z>
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Re: Malevolent Crab? 4/4/13
Thanks Lynn.
<You’re very welcome.>
The crab, with its arms extended is about a 5 inch span.
The head is about 1.5 inches across.
<Whoa, yep, I’d be finding those crabs a new home! Take care, Lynn Z>
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Desperately seeking crab removal advice
8/9/12
Hello Crew,
<HC>
I am starting up a new tank. I have my live rock (Fiji rocks)
curing at the moment. In fact, it has been more than 4 weeks
curing. I was about to place the rocks in my display tank. I
picked up one piece, to my surprise, 2 or 3 little crabs went scurrying
into the rock crevices. These are small little crabs, about half the
size of a penny (or smaller). From reading your Crab FAQ sections, I
know crabs are bad news for a reef tank or most tanks for that matter.
I want to remove them. What removal method would you advise?
<... trapping... As posted on WWM>
I was thinking a freshwater dip for the live rocks. But this would
mean I have to re-cure the live rocks. Very much appreciate your
advice. Also, thank you for the wonderful service through out the
years.
Warmest Regards,
HC
<And you, Bob Fenner>
coral guard crab
4/15/12
Dear Wet Web Crew,
<Hi Wendy, Jordan here>
I’ve purchased a 3” Stylophora and have just found that it
contains a commensal crab.
<Nice freebie.>
From the size and shape of it I believe it to be Trapezia.
The coral and crab are currently in quarantine, but will go to my
180 gal reef tank afterward. I would like to know if you
would consider the crab a hazard to any other corals (or fish),
and your opinion on whether the small colony of Stylophora would
do better with or without it?
<I would leave the crab in the coral. The Stylophora is large
enough to withstand any damage the crab may inflict. Smaller SPS
should be safe as the crab is going to find the larger colonies.
It will threaten fish which venture to close to its home but
it's too small to do any real damage.>
I have read that these crabs eat coral mucus as well as coral
flesh and that this may be detrimental for a small colony, but
also helpful for growth, and that they may migrate to another
coral at night, but only reside in Pocillopora or Acropora (but
am wondering if they really may go into other corals as well such
as a Tubastrea?
<They will stick to SPS.>
I have a very nice Tubastrea which I would not want the
crab to damage.
<Tubastrea would likely eat the crab if it tried.>
My reef tank also contains another 3” Stylophora, a couple of 8
inch Staghorns, a few Birdsnests, plus other assorted LPS and
Mushrooms, and an assortment of fish (Argi, Tangs, Anthias,
Fairy Wrasses, Gobies, Chromis, Clownfish) .
Thank you for your advice,
<Quite welcome>
Wendy
<Jordan>
Trapezia crab id 4/15/12
Dear Crew,
<Wendy>
Attached is a picture of my hitchhiker guard crab which I wrote
of earlier.
Could you comment on whether this crab appears to you to be
a Trapezia, or other ?
< I suspect it is Trapezia digitalis but it is difficult to
say for certain based on the picture. It is either a Trapezia sp.
or Tetralia sp. The two can be easily differentiated by there
claws. Trapezia sp will have claws equal in size; Tetralia sp
will have one claw larger than the other. Tetralia sp are also
smaller and will only host Acropora, Trapezia sp are not as picky
as to which stony coral they call home. Nice hitch-hiker
regardless of genus>
Thanks,
<Quite welcome>
Wendy
<Jordan>
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Montipora Eating Crab 1/23/12
Dear Crew,
<Joe>
I hope that you are doing well!
<And you>
I just wanted to request a quick ID today if at all possible. One
of my Montipora digitatas was bleaching a bit at the tips and
today, I found this little guy attached! So sorry, about the
picture quality but these were the best shots out of about 25.
It's definitely a crab, brownish/red in color, hairy arms as
well as barely visible pinchers (sorry, no microscope). This is
the only one that I've witnessed so far and it seemed to
arrive when the Montipora was added to the tank. I'm almost
certain that it was a hitchhiker. It was accidentally killed upon
extraction from the coral.
<Mmm>
Should I be on the lookout for more? My hunch is that it is a
loner.
Lastly, in your opinion, should I break off the dead section of
coral, or just leave as is?
<Well, hard to say, make that determine, if this little
Decapod is much of a real or potential risk to your Montipora...
the group is generally omnivorous... but there are many crabs
(e.g. Trapeziids) that are found in close association w/
Scleractinians, Alcyonaceans, Pennatulaceans... and more
Cnidaria, that are more commensal than not. Some known to keep
off other predators, improve circulation...>
Thank you!!
Joe
<Up to you to remove or no of course. Bob Fenner>
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Black Crab problem..
11/21/11
I have a reef tank with several residents both large and small. One of
them happens to be a fat little black crab that had been a hitch hiker
on a large porous rock with several caves.
I think this crab is responsible for a few of my smaller bottom
dwelling inhabitants. I've tried to lure it out with food, but the
hermits are all over it.
Do you have any other suggestions other than taking this large rock out
and disrupting the whole house?
Thanks
Tom
<Mmm, yes. I'd bait/trap out all (and save the organisms not to
be removed... in a floating colander perhaps), till you've caught
this crab to remove. See here re: http://wetwebmedia.com/swcrabcompfaq3.htm
Bob Fenner>
Crab ID, removal 10/13/11
WWM Crew,
>Jer<
I finally evicted the crab that had been munching on my button
polyps and macro algae. I believe it to be a gorilla crab,
<A Xanthid? Mmm, maybe... I don't see the usual
distinctive dark tips on the principal claws>
but please let me know what you think. He is on his way to the
LFS to see if they want him. I tried leaning a prescription pill
bottle up against the LR with some mussel in the bottom, but the
next morning, the mussel was always gone, with no crab in the
trap. Not sure how he was pulling off the heist, but he seems to
be a very smart little crab (outwitted me for almost a month). I
finally pulled the rock out that I've seen him hiding in and
poured RO water in the hole which got him moving,
then I used a toothpick to poke him out from the back side. It
was a pain, but I got him out and got to re-arrange the rock-work
in my tank. Since I had the rock-work taken apart, I also did a
RO dip of all the other LR and evicted about 5 flatworms that had
previously gone unnoticed. Win-win!
<Yay!>
Thanks for your advice on the matter, you guys/gals rock!
Jeremiah
<Mmm, read here: http://wetwebmedia.com/SWCrabIDF18.htm
and the other 17 Decapod ID files linked above. BobF>
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Mystery Crab! How to Trap a Crab --
7/20/10
Long time no talk!
<Hi Melissa, Lynn here today!>
That's a good thing!
<Hehee!>
I hope all of you are doing well.
<Yep, we're hanging in there, thanks.>
Short run down on my tank again since it has been a while. Some
equipment has changed too. 125 gallon tank roughly 125 lbs live rock
DSB, Remora Pro, Needle Wheel, (incidentally both of them combined with
water changes finally nipped my red slime in the bud so just kept them
running ;)
<Yay!>
It helped that I stopped the kids from feeding too!)
<Kids do love to feed fish, but it can sure lead to
problems!>
Inhabitants: lawnmower blenny, 4 blue green Chromis, ocellaris, yellow
tang, six line wrasse, coral beauty, royal gramma, Blue hippo tang,
Chocolate chip starfish (Chip) (he is getting huge and getting his own
tank shortly!),
<Good>
2 cleaner shrimp, 4 Mexican Turbos, roughly 20 Nassarius snails, 20
Trochus snails, 40 blue leg crabs. Herein lies the problem. I
apparently have a crab!
<Uh-oh. The funny thing is that I was just thinking the other day
that it had been awhile since we'd gotten a good crab
query.>
A large crab. Almost as large as my palm.
<If the carapace is the size of your palm - yikes! If the whole
thing, legs and all, is that size, that's not too bad but the crab
will need to be trapped/removed.>
I did not purchase said crab and put him in there.
<He's probably been in there awhile.>
He looks to have hairy legs and two big claws. My best guess would be
Mithrax or Emerald although it was not green it was definitely
beige-ish.
<Okay>
It was very shy and skittish.
<Understandable. That's probably why he's gone undetected
for so long. Chances are good that up until now, he's done most of
his foraging at night.>
Grabbed an algae wafer right up and went to town. I had put one in for
the blenny and he grabbed it instead.
<Yep, now that he's fairly sizeable, he'll require more food
and become increasingly bold in his attempts to get it. An
opportunistic, hungry crab is not a good thing around fishes or other
desirable livestock.>
I will try to get a picture but I doubt I will have much luck with
that.
<That's okay. Basically, a crab that large is better off in its
own tank or with other 'tough guys' that won't end up as
prey.>
I have a net buried in there now in hopes of catching it. Again, not
likely.
<Crabs can indeed be a challenge to capture/trap. Choice one
includes hoping the little fellow comes out of the rockwork far enough
so you can net him. Unfortunately, they're wary and quick, so that
rarely works. Choice two involves going Rambo on the guy and tearing
the tank apart to get to him. That's never fun and should only be
done as a last resort. What I recommend is choice three: baiting him.
The advantage of this is two-fold. First of all, keeping the crab fed
helps deter predation and allows you time to desensitize him to your
presence, as well as that of a net or other trap/set-up. With a crab
that size, you'll need a fairly large net, jar (like a clean,
wide-mouth pickle or mayo jar), or even half of a plastic water bottle.
Unfortunately, the above methods require your presence in order to
complete the capture, but it's better than taking a tank apart! If
you're going to use the net method, place it near an open area of
sand (maybe near a corner to limit his escape routes) and lure him
closer each day. Hopefully, he'll come to associate the net with
being fed or at the very least, not see it as a threat. Once he's
comfortable approaching the net, reach in, grab it, and get him.
You've probably got one shot at this method before he gets wise to
what's going on, so make it count. As for the jar/bottle method,
there are two ways to go. For something like a heavy pickle jar,
tip/wedge it against the rocks (where you think he hangs out) and bait
him in there. Once inside, he won't be able to climb up the slick
walls and will be trapped (unless he can reach the lip). You can
probably leave this type of trap in there overnight, unattended. As for
the plastic water bottle method, you can use either end of the
container. Just make sure there's enough room for him to get in and
not get out quickly. Using a hole punch, place two holes about an inch
or so apart and about an inch or so away from the open/cut edge, and
attach some fishing line (enough to extend out of the tank). Lay the
container on an area of open sand and bait him closer over several days
(however long it takes). Eventually, use something like a turkey baster
to get the bait inside the container towards the back. Watch and wait
for the crab to go in. All you have to do then is grab the fishing line
and pull him up! If you use the top half of a water bottle, and remove
the cap, it's easier to pull up since the water inside has a place
to flow through. The small, open lid also gives you a handy place to
aim some food to the back of the trap. I know all of this sounds like a
time-consuming pain but it's worth it. It's either that or go
Rambo on the guy!>
As for how it got there, I have not purchased anything for quite some
time. The last thing was the Blue Tang and I certainly would have
noticed a crab with it.
<No kidding, so would the Tang!>
And ironically even my rock was not "live" I bought the stuff
dried in a box. My first piece of live rock was almost 4 years ago or
whatever. I have done the rest on my own. I am thinking it came with
the other crabs a few years ago and I did not notice it.
<Possibly so, or in with that rock from four years ago.>
The question is, Do I keep it or no?
<I definitely wouldn't keep it in the present tank.>
Can I put it in the other tank with Chip? He is a large starfish. He is
easily 8 inches across now.
<Wow, that's a big one. I'd go ahead and put the crab in
with the star, keep both well fed, and see how it goes. If you see any
signs of predation, remove one or the other right away.>
I only have live rock in the tank currently, but feel comfortable
enough with all of my equipment and knowledge to move on up to
corals.
<Good for you for being patient and not jumping into corals right
away!>
Anyway, the crab freaked me out. It is big and hairy. I thought it was
an octopus at first glance.
<Hehehee! I had an epitoke (a Polychaete in a reproductive phase)
scare at least ten years off my life a few years back so I know the
feeling. I'm embarrassed to admit that I screamed like a little
girl!>
I do not know how in the world I could have missed it.
<Again, he'd probably been hiding out in there for awhile, only
coming out at night.>
There is so much rock work though it got away from me almost
immediately.
<That's frustratingly typical.>
I am worried about my fishy friends. Your advice is much appreciated.
Thanks again!
<You're very welcome and good luck!>
Melissa
<Take care, Lynn Z>
Sally light foot, and Stenopid comp.
7/12/10
Hello,
I'm back with more reef questions...
I have a 180 gallon tank (empty but with water/rock) and I was
wondering if a mated pair of coral banded shrimp and 1 sally light foot
crab would be okay together.
<If they don't get too hungry>
Except for a fair amount of snails
<They may eat these>
as the only other invertebrates, these guys would be pretty much the
only inverts in the tank. Fish-wise, there would be a school of green
Chromis', 1 Pseudochromis, a Sixline wrasse, a algae blenny and 3-4
PJ cardinals.
Would this overall combination work, again a 180 tank
[6'x2'x2'], or should I expect WWIII between one or more
things in the tank?
Thanks in advance,
Tristan
<See WWM re crab and boxer shrimp compatibility. B>
Sally Light Foot/Sally Light Foot Compatibility/Crab
Compatibility, James' go 7/12/10
Hello,
<Hi Tristan>
I'm back with more reef questions...
<OK>
I have a 180 gallon tank (empty but with water/rock) and I was
wondering if a mated pair of Coral Banded Shrimp and 1 Sally Light Foot
crab would be okay together.
<I would not chance. When large, they are capable of catching and
eating shrimp and other invertebrates.>
Except for a fair amount of snails as the only other invertebrates,
these guys would be pretty much the only inverts in the tank.
Fish-wise, there would be a school of Green Chromis', 1
Pseudochromis, a Sixline Wrasse, a algae blenny and 3-4 PJ cardinals.
Would this overall combination work, again a 180 tank
[6'x2'x2'], or should I expect WWIII between one or more
things in the tank?
<Looks like a peaceful clan. The Sailfin/Algae Blenny (Salarias
fasciatus) does better in aged systems where some algae is present. If
not, supplemental algae feedings will be required. May want to read
here. http://www.wetwebmedia.com/algaeblensart.htm>
Thanks in advance,
<You're welcome. James (Salty Dog)>
Tristan
Re Sally Lightfoot... now Mithraculus Compatibility/Crab Compatibility
7/12/10 - 7-14-10
Hmmm...(thinking about your reply)
Both you and Bob said that the two would not get along, I didn't
expect that they would, I was just crossing my fingers and thought I
should ask, hoping the tank may be big enough. Would a handful of
Emerald Crabs be okay
with the Coral Banded Shrimp?
<Generally safe, but they are an opportunistic feeder, and if food
is not available to them, they may turn to supplementing their diet
with corals or invertebrates.>
Otherwise what non-hermit invert would work; helping to keep the bits
of macroalgae growing in check? I'm a bit reluctant to put in a
urchin because I don't want it to knock stuff over and I would like
to keep as much of my
coralline algae as possible. I'm at a bit of a loss as to what
could work.
<The Blue Tuxedo Urchin (Mespilia globulus> would be one, as they
are much more forgiving in terms of rearranging your rockwork. You may
want to read here and related links in the header for methods of
controlling algae.
http://www.wetwebmedia.com/algaeconMar.htm.
James (Salty Dog)>
Tristan
Re: Monodactylids and Crustaceans, predators for the latter
5/24/10
Thank you for the reference to the website. It should help a great deal
with species-specific information.
I was wondering what you meant by purposeful predator control. I take
that to mean finding something that preys on crustaceans and using it
to prevent the crabs from overrunning the tank. If so, do you have any
suggestions as to organisms that love eating crab as much as
Boston?
<Mmm, the groups that come to mind are Balistids, some larger
Labrids, Stomatopods... You should be able to find input re these and
other crabs principal predator groups in a library search, maybe even
the Net. B>
Crabs, control 4/13/10
Hi Bob,
<Andrew>
I've got a crab problem due to some aqua cultured rock, and I'm
seeing why a lot of people like to use dry base rock.
I've instigated 2 major battles against Xanthid crabs since I
started the tank, and I guess pulling the rock and flushing every hole
with freshwater didn't get them all to run off. Now, about 2 months
later, I'm catching as
many crabs per night as I was before I did the house cleaning where I
caught about 65 crabs. I found that they were in the tank because
they're bothering some of the corals (Pretty much everything that
isn't a Goniastrea or
Acanthastrea; it appears that they're living inside the Astreas,
but not hurting them too much, as they will still eat normally. Are
gorilla crabs known to be commensal or symbiotic with corals?)
<Can be... but if too many, hungry, can be trouble>
I'm wondering if there are any shrimp, fish, or other additions to
an aquarium that are heavily biased towards eating crabs, gorilla crabs
in particular.
<Best to trap them out>
I know mantis shrimp would be an effective option for crustacean
elimination, but I'm not sure if they would be a good fit, as there
are young kids who may tap on the tank and "taunt" one to the
point of breaking the glass,
<Doubtful>
an outcome I wouldn't be able to handle financially or emotionally
after all the work that has gone into this tank. Are there any other,
slightly less risky shrimp or other animals that would fit into a
"crab control" role?
Andrew Angrist
<Trouble is, a predator may consume other livestock you'd like
to keep as well... Please read here:
http://wetwebmedia.com/swcrabcompfaq2.htm
and the linked files in the series above.
Bob Fenner>
Crab ID 1/4/2010
Hello Crew.
<Erik>
I am in the process of trying to catch some of the crabs in my
Red Sea reef tank. Most all need to go. I have already caught one
shamefaced crab.
There is at least one more of these. I have attached a picture of
one crab that may be ok to keep. I believe it to be a Black
Mithrax. Note in the picture the round plates at the end of the
pinchers. He feeds heavily on algae, but obviously will consume
meat as a small piece of shrimp was used as the bait. Should he
stay or go?
<Mmm, please see Lynn's input on our forum, here:
http://74.125.155.132/search?q=cache:ZjLAMxocUDcJ:bb.wetwebmedia.com/viewtop
ic.php%3Ff%3D25%26t%3D189+black+mithrax&cd=1&hl=en&ct=clnk&gl=us
Also, many of the other crabs are very small and I have not had
luck
catching them in the traps. Only the larger crabs get caught. Is
this normal?
<Not atypical, no>
I am using a small canning jar tilted against the rock with a
small piece of shrimp in the bottom. Is there a better trap for
smaller crabs?
<Whatever works... the small, all-plastic rodent traps (or
repackaged/labeled ones for aquarium use) from Home Depot,
Lowe's et all... are my faves... have a dropping un-openable
(by them) trap door... aka "Have-A-Heart" traps for
terrestrial use>
Thanks again for all the great information. I am certain I would
not be having the success I am having without this site.
Kind Regards,
Erik Hayes
<Welcome! Bob Fenner>
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Coral Attack, Zoas vs. Decapods 9/16/09
Need more help.
<I know I do>
I have a 135 with 150lbs of live rock. Nice and purple. Nitrate is less
than 10 and on its way down, as I just installed a RDSB. I found a
single Zoanthid growing on the rock and figured it was a good time to
put a few test corals in. I put in a small frag with about 10
Zoanthids. The Zoas were attached to the skeletal remains of
something. It was not a rock. The first night one of the hitchhiker
crabs apparently removed the coral from their attachment and took the
structure away.
<Wow; strong crabs>
I found the Zoas on the bottom curled into a ball. I have replaced
them in another location and they are slowly moving up the rock.
Is any of this normal? Will the Zoas recover?
<Mmm, hopefully. You might want to rig some sort of strong cover
over them for now. Maybe a plastic "berry" container,
inverted, tied down with all-plastic ties.>
I have seen 3 crabs. Based on their claw configurations, 2 need to
go.
The last time I tried trapping, nothing happened. I assume crabs do not
hunt during molting?
<For the most part this is so>
I found sheds during the time I tried the trap.
I really appreciate all the great information on the site and in the
Bob's books. The entire family is having a great time learning and
watching new things happen every day.
<Ahh, great! BobF>
Thanks,
Erik C. Hayes
Decorator Crab; Feeding And Compatibility
8/30/09
Okay, so my roomy and I recently set up a 25 gallon salt water aquarium
consisting of crushed coral and about 8 lbs of live rock. We decided to
throw in a Spider Decorator Crab to entertain us while we
wait for the tank to finish curing and ammonia levels to get as close
as possible to zero :) (we made sure they were pretty darn close to nil
before adding the crab).
Squeegee, as we named him, seems pretty content, scavenging the tank
for whatever he can find on the live rock, not-to-mention the
assortment of tropical flakes that we throw in on a day-to-day
basis.
This leads me to my first question. Are the flakes enough for the crab
to eat and if so how many should I be throwing in there? Also, would
feeding the crab ghost shrimp be okay (if so how many a night)?
<Ghost shrimp are fine, maybe one every other day depending on the
crab's size. Kind of pricey for crab food.>
And lastly, Is there a more ideal (and cheap?!) sustenance we could be
feeding it?
<Flakes are fine and about as cheap as you can get. A few flakes per
day should keep him happy. Crabs are opportunistic scavengers and will
eat most anything they can find.>
Finally, as far as compatibility goes... the tank was originally
intended for a Snowflake Eel (no fish) which we'll be getting as
soon as the tank is ready. Do you think a young (6in) Snowflake would
attack/devour Squeegee?
<A excellent chance for this to happen as crabs and shrimp are their
main diet in nature. Do be aware that your tank will eventually be too
small for keeping a Snowflake Moray in good health.>
Would there be any way that we can get them accustomed to each other
with adequate feeding long enough so that they can coexist for some
extended period of time?
<No. Do read here.
http://www.wetwebmedia.com/snowflakemoray.htm>
Thank you!
<You're welcome. James (Salty Dog)>
Black Mithrax Crab HH, incomp. 8/7/09
Good morning crew,
<Hi Jessy here>
I have a few questions about a hitchhiker. I've actually been
trying to catch it for a month or so, but I've never had any
problems with it until now. I have identified it as a black Mithrax
crab. it looks and feeds like
an emerald but black with very hairy legs. (That's kind of a
"duh" statement isn't it?) I recently had a pistol shrimp
and a black ray goby pair up and make a burrow underneath my live rock.
I came home one day to
find the shrimp gone and his goby hiding. Later the goby abandoned the
burrow and the black Mithrax emerged from their den. The next day the
goby returned for a while, and that was the last I saw of him again.
The Mithrax isn't bigger than the goby, but could he have eaten
them both?? I would think the goby would have protected his buddy, but
maybe I'm confused. If this crab did kill them both, how do I trap
the SOB?
<Jake, unfortunately that is probably exactly what happened to your
poor pair. Those little devils of a crab are bad. To trap them,
I've heard many things. They are much like mantis shrimp...hard to
catch. I've heard of everything from a small glass jar being buried
neck up in the sand for the crab to crawl into with food as bait, but
not be able to get back out of.
I've heard of outright spearing the little buggers, but that seems
a bit extreme and skilled. The last way I can suggest is figuring out
what rock the little guy stays in and removing that rock from the reef
to be flushed
out in fresh water or prodded until you can better see the culprit.
Either way, it is not going to be an easy process. I wish you
luck!>
Thanks,
Jake Maenius
<Regards, Jessy>
Zoanthids Disappearing, Hitchhiking Crabs --
7/18/09
<Hello Jared, Lynn here this afternoon.>
I have been loosing the expensive Zoas fairly fast each
night.
<Yikes! Have you looked for the usual suspects? Please see the
following links for more information/photos:
http://www.zoaid.com/gallery2/main.php?g2_itemId=384
http://www.zoaid.com/index.php?name=FAQ&id_cat=3#q15
http://www.wetwebmedia.com/zoanthidcompfaqs.htm >
The ugly cheap ones are doing great just like kudzu (of
course).
<Murphy's law strikes again.>
I have lost a quite a few whole colonies of tubs blues, gorilla
nipples, fire and ice, black cherry and so on. In all about $300
of Zoas!!!!
<Yowza!>
I pulled out my trusty red lens light 3 nights in a row and found
this guy in a hole near the Zoas. Now I do not know if he is the
culprit, as he does not have the really fuzzy bear legs or sharp
claws on the ends (they are flat and look just like a emerald
crab)....so a rogue algae eater gone to the dark side
maybe????
<I don't think the crab was actually eating the Zoanthids,
but it's possible that his presence was acting as an
irritant. In which case, you'd have noticed the polyps
remaining closed for extended periods of time (not disappearing
overnight). I guess it's always possible that, for whatever
reason, the crab was pulling the polyps off the rock. I just
don't know. What you describe sounds more like deliberate
predation. I'd look for Nudibranchs, Heliacus/sundial snails,
and others listed at the above link. One other thing to do though
is check the remaining Zoanthids for any sign of small
light/whitish spots. If so, it could be what some hobbyists call
Zoanthid pox. Please see this link for a photo example:
http://www.zoaid.com/gallery2/main.php?g2_view=core.DownloadItem&g2_itemId=3573
For treatment, see first FAQ, titled 'Zoa Pox Treatment --
05/09/09' at this link:
http://www.wetwebmedia.com/furancpdfaqs.htm
More info here regarding diagnosis/treatment:
http://www.wetwebmedia.com/zoanthidhlthfaqs.htm
>
Plus he lost a leg battling me.
<Oops!>
I accidentally skewered it with a bamboo skewer and was able to
force him out of the hole that way. I have him in my fuge with
easy access to remove him, but I have found 2 more EXACTLY like
him in another piece of base rock. And of course they are either
too far in or they scurry away before I can get them.
<No kidding. They know they can't win a battle against the
skewer-man!>
Zero damage as of yet from them, but I am still trying to get
them.
<I would do the same.>
He looks very similar to the header pic and last pic on:
http://www.wetwebmedia.com/Arthropoda/CrustaceanPIX/SWCrabs/Crab%20IDs/swcrabid12.htm
<Gotcha. Although those claw tips look fairly blunt, they
don't appear fully spatulate like those of
emerald/Mithraculus crabs. Also, the presence of hefty molar-like
('molariform') structures on the inside edges indicate
that the claws are less adapted for eating algae and more adapted
for crushing -- usually mollusks. Crabs on the whole are
omnivorous creatures. They're usually okay in reef tanks when
small, but can be a problem as they grow larger.>
What do you guys think????-- Trigger/octopus food or not?
<Well, the trigger and octopus would definitely love it, but
I'm a softie; I'd spare their lives and find them a new
home in the sump or elsewhere.>
Jared
<Take care, LynnZ>
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Crab stow away and dead shrimp/snails 5/1/09
Hi
<Hello>
We are new to your site and hope that you can help us. We have a 30
gallon marine tank and just discovered that we had a stow away crab. We
assume it was in the live rock. We found two claws and a top shell that
was about 1" and 1 1/2" across which was white with brown
spots. The crab type really doesn't matter as we have lost 2
peppermint shrimp, 1 fire shrimp, and about 20 snails in the past
month, so we hope to get it out of the tank.
The thing is, my husband moved our fish to a quarantine tank (hopefully
to save them from becoming dinner, and he removed all of the sand as
well to a couple bowls trying to shift to find the crab. He didn't
find a crab but he did find 3-4 solid white mucus chunks with a few
black lines in it. The chunks were about 1/2" each. Could this
possibly be the remains of the crab if he squished it?
<Possibly, but he is probably hiding>
Last night we saw the first claw so we think it must have just lost
it's shell. We want to know if we have accidentally taken care of
the crab (by squishing him) or if he is most likely hiding in the rock.
Needless to say we don't want to keep feeding him our daughters
fish for dinner.
<A trap might be your best bet. Commercially available traps are
normally pricey, but you can actually make one yourself by burying a
glass jar in your sand bed and baiting it. The best time to do this is
likely at night, the crab should go for the food and then have
difficulty climbing out of the smooth jar.>
<I suggest reading here
http://www.wetwebmedia.com/marine/inverts/arthropoda/crabs/swcrabfaqs2.htm
>
Thanks,
Tami & Mark
<Your Welcome
Josh Solomon>
Decorator crabs. Comp. 04/03/09
Hi, i have 2 decorator crabs in one 30 gallon tank, they were fine when
i brought them home a few weeks ago and were small. Once they got a
little bit bigger it seems they try to eat everything.
<What they do>
I have never dealt with this type of decorator. It's the sponge
decorator variety of crab.
<There's more than one species...>
Should i get rid of both or just one?
<... what do you want to have else-wise?>
I planned on getting a different species that i have had experience
with but not this one. I was given these two when i ordered a different
type of decorator.
<Mmm, I'd likely trade both in... you will have
"issues" with one, two... in any case. Bob Fenner>
Need to rid my reef tank of an Emerald Crab! A Suggestion
3/23/09
Hello,
<Hi there James, Mich with you.>
Great site by the way.
<Glad you like it!>
I made a terrible mistake and put two emerald crabs in my reef tank.
Why a LFS would sell these things is beyond me
<They have their uses I suppose. But I personally am not a
fan.>
but I was dumb enough to buy two, not one! I have found out the hard
way that these crabs only eat coralline algae off of live rock, or
better yet, coral polyps, and this is also based on other reefer's
experiences with these crabs on other blogs. I tried your raw fish in a
jar trap and the male went for it after a few hours and I got him out
(yea).
<Yay!>
The female crab will not go for anything even if its a few inches away
and stinks really bad!
<Heehee! Perhaps the females of the species are smarter than the
males?>
Is there any other way to get this miserable creature out of my tank if
raw meat doesn't work?
<Well I don have a suggestion but I'm not sure you'll like
it.>
I think I would rather pour bleach in my tank
<PBITAWA???>
and deal with that than watch this thing eat every polyp off my corals,
oh yea, and my coralline.
<Well here's my trick. It sounds like you know where she lives.
You need to remove that rock. Take that rock and put it in a long
under-the-bed type plastic storage container filled about a quarter of
the way with water. Elevate one side of the container and put the rock
in the area that is the deepest. Then gradually over the course of say
2 hours or so move that rock higher up the incline so the rock is in
ever more shallow water.
Make sure you put some PVC or some small rubble in the deep end of the
water so the crab has some place to hide. But the crab in my experience
will want to stay in the water and you will likely find her hiding in
the safety of the hiding places of the deep end. I know you are
probably not very fond of her right now. But please, this animal is
doing what she has evolved to do, have mercy on her, care for her
responsibly, move her to your sump, return her to your LFS or find
someone who can provide her the care she needs.>
My tank is a RedSea Max 250 (65 gallons). Thanks for all your great
support.
<I hope this helps!>
James
<Mich>
Good crab or bad crab?? 01/22/09 Hello Crew,
I have several. Purchased from a fellow hobbyist as reef safe. He
said that they are emerald crabs, but they are more Tan with dark
green pigment than all dark green. <One of the troubles with
common names... there are several species of Mithrax crabs that
sometimes get lumped under the common name "emerald
crabs." The green ones are the Mithrax sculptus. But there
are other species which look a lot like M. sculptus, but that are
more red or brown (some are even black).> I have had them for
a few months with no damage, but I realize that I am not sure
what they are, <Possibly M. forceps... but it's very hard
to make much out in the photo.> which is a bit unnerving.
(Yes, I should have been more considerate before adding them)/
The claws are light. If they are in fact bad, what is the best
way to remove/catch them. <No crab is 100% reef safe. But the
Mithrax crabs tend to behave themselves more than most when
they're well-fed. They are good scavengers and algae pickers.
I wouldn't remove them unless they start to become a problem
(i.e. just keep an eye on them).> P.S. Pic is in the worst
corner of the tank. Ignore the Kenya tree and Aiptasia please.
Thanks very much, Mitch <De nada, Sara M.>
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SW Crab Question, incomp. -- 01/13/09 Evening crew,
from snow buried Chicago! <<Greetings Heather'¦ From a
somewhat more pleasant South Carolina>> A few weeks ago while
gazing at my tank, I discovered a new (well, not quite new, but now
large enough to be noticed) inhabitant, a crab.
<<Mmm'¦>> From the searching I've done with
Google on WWM, the closest comparison I could find was the Banded
Clinging Crab, Mithrax cinctimanus, but that is a rough comparison.
<<Okay>> My crab is now about the size of a dollar coin,
roughly an inch wide body. It is a dark brown/black base with orange
markings or "patches". My tank is a 55 gallon with live rock,
a Royal Gramma, two Ocellaris Clowns, two Skunk Cleaners, and five
Peppermint Shrimp. The Peppermints have only been in the tank for two
weeks. I did a head count last night (somewhat difficult to do with
60lbs of live rock...) and all are still present. I was wondering if I
should be concerned about my newly discovered crab harming any of my
other inhabitants, mainly the shrimp? <<Very possibly,
yes 'and the fish too. Even if this is a species of supposedly
'reef safe' Mithrax crab, large specimens are known to pose a
hazard re. If this is not a Mithrax species, the concern/hazard is
likely even greater as this crab continues to grow>> If it does
pose a threat, how is best to remove him? <<This can prove
difficult'¦ A trap of some kind'¦ Perhaps a small jar
baited with a piece of meat of marine origin placed in the sand or
among the rock. Do also peruse WWM re 'crustacean removal' for
other's thoughts/ideas>> It seems to us that he has grown
since discovering him, so my hopes of him not getting any bigger are
gone. <<Indeed>> Thanks much for everything you guys do!
Mr. Fenner's book is one of my most read! -Heather <<Happy to
share, Heather. Good luck with trapping that crab. EricR>>
Crab eating open brain?? 01/04/09 Hi there!
<Hi> I have been spending a lot of time on your site and it
has helped me tons! I have also listened to Bob (just bought your
conscientious book) Blue zoo Radio which I listen to and love! I
have a question I needed to write in for... I have a 29g mini-
reef, running now for 3mos. Ph 8.2, 78 degrees. N , No2, and No3
all 0. Ca 380, KH 8. I am running a Current Satellite 30"
60w SunPaq dual daylight, dual actinic, w/moon for lighting. I am
also using a hob filter using foam, and carbon, an AquaC remora
skimmer, both hung on the back of tank, and 2 powerheads placed
in the top front corners of the tank pointed to the opposite
lower back corners of the tank. My tankmates are: 1 turbo, 1
Trochus, 1 emerald crab, 1 peppermint shrimp, 1 blue knuckle
hermit, and around 8 mini hermits. I have a few small Seastars
that hitchhiked into my tank as well. I acquired 2 colonies of
Zoanthids, a sponge, some tube (feather dusters?) worms, and some
mushrooms on my live rock. The corals I purchased, were acquired
from the same LFS; Euphyllia Frogspawn, Dendrophyllia (my
favorite) , Caulastrea Candycane, Xenia, Nephthea, Diaseris, and
a Trachyphyllia g. (pink and green). All seem to be doing great,
(with the exception of my Trach, which brings me to write to you)
expanding fully and eating. <This is a lot of different types
of corals for such a small tank. I would expect some chemical
warfare problems... if not now, then in the near future.> My
question is about my open brain. He's been in my tank about 5
weeks . I originally had him up on a rock, just an inch above the
sand, but my pesky blue knuckle hermit kept mowing him over into
the sand, along with everyone else! I have since used Aquastik to
glue all my corals to the live rock, and put my brain onto the
sand as I've read is better on your site. <Ah, good.>
He seemed to settle in, expanding during the day, after having
what seemed to be a tough few days. He did still eat a small mash
of raw shrimp 3 days ago. I tried to feed him yesterday, and a
puff of brown 'smoke' came out of one of his mouths.
Good/bad?? <It is likely expelling waste (maybe even expelling
Zooxanthellae-- judging from how it looks a little pale, this
could be "bad").> Tonight, after my actinic lights
shut off, I found my Blue knuckle hermit on the edge of my open
brain. The hermit looked like it was shoving his legs and claws
into the edge where the pink outside, meets the green inner side
(where the brains mouths are) kneading it like a cat. I tried to
move it away from my brain , but it grabbed hold, and
wouldn't let go. I tried luring it off my brain with a piece
of krill, but it was more interested in pawing at my brain for a
bit longer until the brain was totally drawn into its skeleton.
It finally lost interest and moved on . Was my Hermit eating my
Open Brain coral?? <This is a bad sign. Hermits are mostly
opportunistic eaters. It was likely either trying to steal food
from the coral, or picking at weak tissue.> Is my Trach dying?
Should I remove my Hermit? <Possibly, unfortunately-- but the
good news is that it's far from dead just yet. Yes, I would
remove the hermit and target feed the coral.> 2 last
questions; What other corals do you think would be a compatible
next purchase to go with the corals I already have? I would love
to buy 3 or 4 fish. Any suggestions?? <IMO, you have too many
different types of corals already. As for fish... keep them small
and few, gobies, Chromis, maybe Perculas... please read, research
thoroughly before purchasing.> I have attached a picture of my
Trach that I took just yesterday, and a pic of where things are
set up in my tank. Thanks for taking the time to answer my
questions!! <Good luck>
<Best,
Sara M.>
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Hitchhiker Crab and Dwarf Morays, comp.s
12/02/08 Hello, <Hi Paul.> I recently ordered two
Gymnothorax melatremus (Golden Dwarf Moray) and plan on putting at
least one of them in an established 58 US gallon reef aquarium. Would
it be advisable to put both eels in the same aquarium as they are not
actually a mated pair? <Preferable, sometimes found as pairs in
nature. Your two may become a pair and should only be separated if they
start to fight severely, which is less probable even if they have the
same gender.> If not I can place them in separate tanks easily.
<I'd leave this option if fights should start. In this case one
will more easily be caught with net.> My second question concerns a
Xanthid crab that I recently found in the 58 gallon reef. More
specifically, I found a molted carapace approximately one inch across
along with claws and other bits of old crab exoskeleton. Will this crab
pose a danger to the eel(s) if I put them in the tank before I can
capture the crab? <If the eels are at least 6" they should
rather be a danger to the crab. If they are significantly smaller
I'd catch the crab with a crab trap just for peace of mind.> I
already believe he has killed fish in the tank as a pair of Banggai
cardinals went completely missing several months ago. I did read
somewhere that golden dwarf morays would eat invertebrates, but would
one be able to take down a crab of this size? <Depends on their
size, physical condition, crabs are their favourite food. Healthy
specimens of 6" should be safe, only dead/dying small eels (this
reclusive and expensive species is sometimes caught with poison) may
become crab food. I've seen relatively small morays tearing off
pinchers of crabs they could not eat as a whole. They are able to tie a
knot into their body and pull their head and the prey item through the
knot.> In any case the morays will go into a quarantine tank, at
least until I hear back from you. <Okay.> Many thanks, Paul.
<Welcome. Marco.>
An answer, rather than a question! Crab eating SPS
09/18/2008 <<Good day, Bob, Andrew today>> I
see a lot of posts asking about crabs. Here area couple of very
good pictures of one that I guarantee is an SPS-eater.
<<Heeeee...i would certainly agree>> The coral he
lived on was getting 'tracks' all over it of nipped out
polyps, etc. After he was removed, the coral completely
recovered. Feel free to use the pictures as you like.
[IMG]http://i226.photobucket.com/albums/dd7/Coralmaker/crab2.jpg[/IMG]
[IMG]http://i226.photobucket.com/albums/dd7/Coralmaker/crab1.jpg[/IMG]
bob <<Two really great shots there Bob, and they will
certainly be welcomed into our picture database. Thank you very
much for providing / sharing two wonderful pictures. Kind
Regards, A Nixon>>
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Pom Poms and Croceas 9/9/08 Hi there guys, I have a
nano 10 gallon with a 175W Metal Halide on it. <"Giant steps
are what you take, walking on the moon/sun"> It has a 2.5
gallon sump/fuge with mangroves growing in it. 14.5 pounds live Rock,
10 Pounds Live sand, assorted sps and LPSs plus Zoos and Palys,
Established tank, 9 months old. Ok, so my question is this. Stinging
corals, especially LPSs, can harm clams very easily if they get too
close. But can anemones do the same? <Yes> More specifically, I
want to get a pom pom crab because I think they are very interesting,
and well, just plain cool, but would this Crab hurt my clam. My
porcelain crab and my emerald crab both love to climb over everything
and make a mess. Could this be problematic with a pom pom and a clam?
Thanks, Andrew <Some chance, but most Lybia avoid the mantles of
clams... The real issue here is going to be "just
size/volume"... When, not if, "something" goes awry
here, there is going to be very little "wiggle room" or
reaction time to prevent a complete melt-down. Bob Fenner>
Re: Gaudy clown crab 4/16/08 Thank-you for
replying. Today our shipment of live rock arrived of 85 pounds. When we
were done placing it all in our aquarium we tried to get the gaudy
clown crab out but it was wedged so far into that one rock it
didn't make it. <Sometime later then... baiting, trapping...>
Later on tonight we were looking and in the corner of our eye we
noticed a second one. Now is it safe to keep in our aquarium?? Or
should we put it in another tank? We have fish and shrimp and blue
legged hermit crabs etc. Please reply and let me know thank-you
<Please read here: http://wetwebmedia.com/swcrabcomp.htm and the
linked files in the series above... till you understand your options
sufficiently. Cheers, BobF> Re: Gaudy clown crab 4/16/08 I
looked on that site that u <...> gave me there was nothing on
there about gaudy clown crabs. Im sorry to be bothering you again its
just no one around where I live knows anything about them. I would be
grateful if you helped me know more about the gaudy clown crabs.
<... Please read generally re the Compatibility of marine crabs
period... B>
Mystery Crab: Possible Xanthid - Cute But Not
Reef Safe - 1/21/08 Hello <Hi Lisa!> I was hoping you
could help me ID this crab: <Will sure try!>
http://i61.photobucket.com/albums/h61/coppersunflower/IMG_0443.jpg
http://i61.photobucket.com/albums/h61/coppersunflower/IMG_0449.jpg
It came into my tank hiding in a rock I recently purchased. It is
quite small (less then a half inch), is white in colour and
appears furry. I've found nothing that resembles it online.
<Heeeee! I don't know what's going on, but suddenly
everyone's asking for crab ID's! Hmmmm, note to self:
Write article for WWM titled: 'Guidelines for Successful Crab
Identification'! These little guys can be notoriously
difficult to ID. It's all in the details! Each family/genus
(not to mention: species) has its own set of distinguishing
characteristics. Sometimes they're very obvious and easy to
differentiate, sometimes not so much. As far as I can tell, the
little crab you have is a Xanthid (family: Xanthidae). These are
cute little guys when small, but can grow to be a real problem
later on. I would not consider it reef safe and would relocate.
Please see these links for more information re:
http://www.wetwebmedia.com/marine/inverts/arthropoda/crabs/swcrabs.htm
http://www.reefkeeping.com/issues/2003-12/rs/index.php .> Any
help you can provide would be greatly appreciated. Thanks
Lisa
<You're very welcome! Take care --Lynn>
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Stylophora pistillata hitchhiker: Xanthid crab?
- 1/20/08 Hey folks! I've got a crab ID request if you
have a moment. <Heeee...these often take many
'moments', but they're always great learning
experiences!> I found a very small (~1/4") juvenile(?)
reddish-brown hairy crab munching/pruning on a Stylophora
pistillata frag I just purchased. <Yikes, was there any
apparent damage?> Distinguishing features include bushy hair
everywhere (body, legs and claws), green eyes, orange claws with
white spots and white tips. The body has white spots as well.
<Well, when you mentioned Stylophora, I was hoping that this
was a little commensal crab in the family Trapeziidae. The
general shape and coloring are right on, but I've never seen
anything in this family that was so hairy. I've seen some
with spiky hairs on the two rear legs, but never all over.
I'm not sure if your little crab is hairy because it's a
juvenile, or because it's a different family/species
altogether. I'm more inclined to think that it's the
latter. If it's not a Trapeziid, it's likely a Xanthid,
and potentially destructive. Not all Xanthids have dark claws.
There are also plenty of species that are hairy, and they're
known to sometimes hitchhike into our tanks within the branches
of stony corals.> I have removed and sequestered the crab. He
was very good at remaining motionless when approached, hugging
the coral. Pretty good camouflage against the brown branches of a
brown/green Stylo! <Typical. Small creatures like this need
all the help they can get when it comes to avoiding predation!
Their ability to blend betters their chances of survival.>
Enclosed is a picture. Sorry for the poor depth-of-focus. I would
like to know what this crab is, and whether or not it will be a
good citizen in my 55g. <Hmmm, wish I could be more help here
but unfortunately, after looking everywhere I can think of, I
can't confirm anything. I'm sure you know the general
rule of thumb that keeping crabs in a reef tank is a risk. Even
commensals can cause problems if they get hungry enough.
Thankfully, that risk is reduced by virtue of the fact that most
commensals stay fairly small. I'm leaning more towards this
little crab being a Xanthid. He/she might be okay for a while,
but not knowing which species it is, I don't know how large
it can get. I'd take a good look where this little crab was
'munching/pruning' on your coral. If it's damaged,
you've got your answer. If not, it could go either way. If
you decide to return it to the tank, just keep an eye out for
problems/damage, and trap/remove if necessary.> Thanks so much
for your time! -Scott
<You're very welcome, and good luck! --Lynn>
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Crab ID Needed -- Acropora Commensal! 1/19/08
Hey, guys and gals -- 3rd letter this week! <Yay! What can I do
for you today?> I bought my first piece of Acropora coral and I
was pretty excited. <Understandably so, they're beautiful
corals!> Well, guess what? A little buddy hitchhiked his way on
the coral! He's pretty much all off white with a bit of
blue-ish purple on his shell. <Yep, I've seen this little
guy's kin before. They're neat little crabs.> He looks
nice and was snuggled in the branches of the Acropora frag but I
have no idea if he's a good guy or bad guy. If he's bad, I
would guess it'll have to be the sump for him until my refugium
gets built! Here are some pictures to help with the ID. Hope they
are clear enough! <They are, thanks! I'm happy to say that
this little crab is a keeper. Ninety-nine percent of the time, when
people write in about hitchhiking crabs, we have to warn them about
the potential risk to their livestock. This, however, is the one
percent that makes for an exception. What you have is a little
Acropora (commensal) crab, in the genus Tetralia. They stay small,
and are actually good for the coral. Interestingly enough, in the
wild, this crab protects the coral from the voracious
Crown-of-Thorns sea star (Acanthaster planci). It pinches the tube
feet of the star and "discourages" it from dining on the
coral! I have a link for you to read through for additional
information, as well as several others with photos:
http://www2.hawaii.edu/~delbeek/afmjan97.html
http://home2.pacific.net.ph/~sweetyummy42/hitchcrabs.html
http://home2.pacific.net.ph/~sweetyummy42/coral_crabs-2.html .>
Thanks, Jon <You're very welcome. Enjoy your new additions!
--Lynn> Jonathan Philpot |
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Hitchhiking crab -- not a good risk 1/18/08 Hi Guys <Hi
Lesley, Lynn here this afternoon.> Hoping you can be as
helpful as you usually are! <Hope so!> I purchased some
live rock today, just to better aquascape the tank. Put it in,
popped out for a few hours, and when I got back, there was this
little bugger sitting there looking at me! <'Yeah,
that's right, I'm a crab...see? I'm going to wait
till dark then eat all your little fishies...see?' Heeee. for
some reason, I've always imagined that if crabs could talk,
they'd sound like Edward G. Robinson. Ever see that old
movie, Key Largo, where he played the gangster Johnny Rocco and -
umm, never mind. :-)> He was easily caught, not very shy, and
approx three inches across. <Fairly large for a hitchhiker --
they're usually pretty small, and shy.> I've managed
to trap him in a breeding trap until I know if he is reef safe or
not (mind you, if he's not, what do I do with him!) <Well,
there are a few choices: set him up in a separate tank, call your
local fish stores/where you got the rock, and see if they're
interested in him, or, if you have online access to a nearby
fish/aquarium club's forums, you can post there and see if
anyone wants him.> I've been all over the site and
can't find anything that looks like him, so do you guys have
any ideas? <Well, I'd need a photo from the dorsal/top
side to get a better idea of what family it's in, but the
bottom line is that crabs are not good candidates for reef tanks.
This is especially true for larger crabs. Large crab = large
appetite and increased risk to resident fish/other invertebrates.
I'd find this guy another home, either in a separate tank at
your place, or elsewhere. Please see these links for more
information re:
http://www.reefkeeping.com/issues/2003-12/rs/index.php
http://www.wetwebmedia.com/marine/inverts/arthropoda/crabs/swcrabs.htm.>
Kind regards Lesley <Take care -Lynn>
Re: Hitchhiking crab -- not a good risk
1/18/08 <Hi Lesley!> Many thanks Lynn, I don't know
what I'd do without this site! <You're very welcome.
As always, it was a pleasure! Take care --Lynn>
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Crab Removal and Tuxedo Urchin vs. Soft Coral --
12/13/07 Good morning, <Hi David!> I'm curious about the
jar method for catching crabs. I took equivalent of a pop bottle,
carefully peeled off the label and scraped off any adhesive... Then I
boiled the bottle in a pot to sterilize it for 5 min.s. Once cooled
down, the bottle was perfectly clean and hopefully sterile. I filled
the bottom with about 3" of sand and placed 3 pieces of krill in
it... The bottle is leaning up against the crab infested
rock...48hrs... No crabs trapped. <Takes time, patience, right bait,
and hungry crab(s).> The largest crab could fit into the bottle
opening sideways. Do you think I'll have better luck if I use more
sand to bring the bait closer to the neck of the bottle? <Can try
this, as long as the sand isn't up high enough to allow the crab to
grab the top edge of the bottle and crawl out. One possibility is that
the krill just might not be 'stinky' enough to lure him/them
in. It sure would have been nice had the crab(s) gone the easy way and
fallen for the jar trap! Since they haven't, and it sounds like the
crabs are all still fairly localized, I'd consider removing the
rock to a bare bottom quarantine tank and thus gaining the upper hand.
One of the many good things about this is that you can control the food
supply. When he/they get hungry enough, they'll go after
whatever's in that trap. It also eliminates the possibility of your
other inverts accidentally wandering in. The main advantage though, is
that the crabs can't wander off and take up residence elsewhere in
the display before you catch them!> This morning I spotted the large
crab likely about 4" away from the Jawfish. <Hmmmm> The
Jawfish didn't seem concerned and the crab was feeding on some
Caulerpa. I have had emerald greens before without incident (mind you
none were this big)... This crab looks identical to the emerald green
Mithrax, except it is black with sandy brown legs. Would you say that
any crab that's of decent size is likely risky in a reef tank with
smaller fish? <Yes> He is kinda neat, but obviously I don't
want to stumble upon a Jawfish carcass one morning. <No kidding!>
If the 'jar method' for catching these critters takes too
long... Do you think removing the liverock and placing in a bucket of
tank water and putting some powerheads on the holes would drive them
out into the bottom of the bucket without damaging the feather dusters
and soft corals? <You could give it a try, but I'm thinking
it's more likely the crab(s) will simply hunker down/go into an
area of the rock that's not getting blasted. There's also a
good chance that it could damage those soft corals. My next step would
be as stated above: QT, control food, trap/net.> I have a fairy
wrasse in quarantine and I suspect the wrasse will find this crab
infested liverock that is so porous with a variety of large chambers
within... Of particular interest for a home. Sleeping wrasse in
liverock infested with a few small crabs and one brute... Ok, maybe I
am answering my own question. Could be disaster? <Heeee! Yes --
something along the lines of 'Come into my parlor, said the spider
to the fly!'. Depending on the size of the wrasse, you might be
able to block off/separate part of the QT with Eggcrate, or
similar.> Lastly, I mentioned my small tuxedo urchin sitting in my
soft coral tubular polyps. I believe he was just passing through. You
had mentioned I should move him. Anyhow, when I came home from work all
the polyps were open and no apparent damage and urchin seemed ok as
well. This is two days later now, again last night Urchin was sitting
in the polyps again. <Hmmmm> I'm wondering if you figure
he's once again just passing through or... Can/does an urchin
actually feed on corals? <According to what I've read, Tuxedo
urchins/Mespilia globulus, rarely eat corals. They're mostly
herbivorous, but if they ran out of algae/got hungry enough...? I'm
a little concerned, about the repeated visits to the soft coral --
unless it's dining on algae on the base/where it's attached.
Would monitor closely for any signs of damage.> Anything I've
read suggests they are totally reef safe. If no damage is being done
I'd like to keep both... The alternative is to move the tuxedo
urchin to my 200g FOWLR tank that houses a Snowflake Moray, Foxface,
Harlequin Tusk, and soon to have tangs/Angel/trigger.... <Would
monitor, relocate if necessary.> David Brynlund <Take care -
Lynn>
Dragonet and Sally Lightfoot Crab 12/1/07 Hello,
I love your site and thank you in advance! My question is regarding a
Sally Lightfoot Crab and my Dragonet ( a scooter blenny or perhaps a
starry blenny). The dragonet is slow moving and just kind of "hops
along" the tank and rock work. Will my newly purchased Sally
Lightfoot be able to catch him and/or is he a threat to him? <Yes it
can. Although it is not a guarantee that he will.> I heard from my
LFS salesman that my dragonet is poisonous to eat displayed by the
bright colors. Is this true and will that deter the Sally Lightfoot?
<They are somewhat thought to be. Do not trust that particular crab
(and several others) in with such a small, slow moving fish.> Thank
you -M. Allebach <Welcome, Scott V.>
Seahorses and crabs 10/16/07 Hi. I recently
purchased a pom pom crab. He is ready to come out of quarantine. I was
planning on putting him in my reef tank, although I have a
Rolland's damsel that is becoming aggressive and may have just
killed my strawberry crab. I witnessed the damsel attack the strawberry
crab the other day. The crab got away quickly, but this morning I found
him laying dead in the sand and am wondering if the damsel is to blame
since the crab seamed otherwise healthy. Plus the new crab is so tiny
that I doubt I will ever see him again in a 55 gallon tank. <Too
likely so> I also have a 20 gallon tank with two young h. erectus.
Would it be safe to house the pom pom crab in the seahorse tank?
<Mmm... a better choice than with the Rolland's...> I know
that anemones and seahorses do not mix, but will it matter when they
are so tiny? Is there any way the pom pom crab would hurt the
seahorses? Thank you all so much for your help. Your website and
helpful expertise are a blessing! -Connie <Thank you. I would take
the risk here myself with the Seahorses. Bob Fenner>
Random questions/reef tank... maint., crab comp., Zoanthid contr.
9/26/07 Hello all and thanks for the great website! I hope this is
not too annoying an e-mail, but I have several somewhat unrelated
questions that I hope I did not miss the answer to in the FAQs. We have
a 90 gallon reef, 4 inch DSB, 120 pounds live rock, with the following
livestock: Naso tang (N. lituratus), <This genus, species needs more
room than this... as stated on WWM...> pair of Clarkii clowns,
mandarin dragonette, double-barred Rabbitfish, yellow tang, cleaner
shrimp, peppermint shrimp, and sally light foot crab. It's the
dreaded "garden reef" <Heee!> with predominately SPS in
the upper third and LPS in the bottom half. However, just to cause
trouble, we have three different types of Zoanthids and two types of
mushrooms. We have a protein skimmer and run carbon. No new fish or
invertebrates have been added in over six months. Thus far, all corals
appear to be flourishing and all fish are happily coexisting. Don't
panic over the stocking..... we are in the process of upgrading to a
220. The tank is finally in and husband is installing the floor jacks
tonight! Parameters are: ammonia/nitrate/nitrite/phosphate-0, SG-1.025,
pH-8.1, temperature-81, calcium-450 mg/dl, and alkalinity-8.5 dKH. So,
on to the myriad of questions......1. The Rabbitfish has developed a
pink hue on both lateral sides just dorsal to his abdominal area. I
have not seen this in any picture of a Rabbitfish, but perhaps it's
just too subtle for pictures. Is this something to be concerned about?
<Mmm, yes... highly likely environmental/stress caused... will abate
with the move to larger, better setting> Fish is eating fine (varied
diet of Mysis and other frozen seafoods, Nori, flake, pellets, etc.)
and acting the same as always. 2. I inquired about a final fish to the
stocking plan and EricR had suggested a powder brown tang. We
weren't crazy about the tang when we looked, so what are your
thoughts on a Sargassum triggerfish? Do you think the odds are good
that this would be a reef safe fish (no guarantees we realize) and that
this an appropriate addition to a peaceful tank? <Are good animals
for larger systems... and not too adventitious as other Balistids...
May still sample your cnidarians> 3. The yellow Zoanthids
(Parazoanthus gracilis I think) have gone absolutely out of control. We
started out with a small rock with perhaps 5 polyps on it over a year
ago and we know have hundreds of polyps. They have grown through the
rock to come out in different areas. <... got to keep them
isolated... on their own patch of rock...> When we try to prune
them, one polyp always seems to escape and then a new colony starts
wherever it lands! They are growing across the sand bed, in the back of
the tank, and even in the middle of other Zoanthid colonies. Any
suggestions for curbing their growth? <Remove as much as you can in
the move to the larger tank> The main polyp area is on a huge rock
that supports a lot of the other rock structure, so removal is not
possible....well not easy anyway. At first they were quite pretty, now
they remind me of dandelions on a manicured yard! 4. Last question and
most important....any hints for trapping the sally light foot crab!?!
<Box traps... you can buy as such or just the plastic ones for small
rodents (they're the same)...> Last month I walked by the tank
to see the crab eating one of the cleaner shrimp (Argh, the horror...I
tell myself the crab was merely scavenging, but....). <Ah, no>
Last week the yellow tang had a tear in the caudal fin. The fin healed,
but we are worried the crab is on the prowl. We have tried physically
grabbing the crab (yeah, no shock that didn't work) and commercial
traps which resulted in one trapped and very stressed clownfish. When
we put frozen fish in a jar or on a string to bait the crab, all the
other fish grab the treat. We have tried feeding the fish on the other
side of the tank at the same time, but they are too clever for that!
Assuming we catch the crab, can we just place him in the fuge or would
one crab defeat the purpose of the fuge, especially since we rely on
the pod production for the mandarin? <Move, isolate, trade in with
the move...> Thanks for the help as always and sorry for the long
e-mail. All of you do a great service to us newbies out here! Michele
<Congrats on the new, larger system. Bob Fenner>
Re: Random questions/reef tank 9/26/07 Thank you for the
reply. Yes, we know the 90 gallon is WAAAY too small for the Naso which
is why we are upgrading to the 220. We didn't do our research when
we bought her last year, but we are trying to make it right with the
new tank. <Good... I do hope you get on out to the wild... see these
active fishes there> The tank was a custom order this past January
right after we got the Naso, but it only finally got here last month!
We had certainly hoped to have her in the larger tank sooner than this.
You have me quite stressed now that the Rabbitfish's coloration is
secondary to the small tank....we shall try and get the new tank up and
running quickly! Michele Frazer, DVM <Do please send along an image
or two when it's settled in. Cheers, BobF>
Crab and
Candycane comp. -- 08/27/07 Hi Crew, Yesterday I noticed
something on my Candycane. In between the outer brown and the inner
green it looked like something got caught on there. So I took a
tweezers and it lifted right out but it came out swinging. It is (was)
tiny and I doubt if I could have presented a good picture. I usually
let things, that I find in the tank, live. But my gut feeling was that
this was a bad guy, at least for my Candycane, so my tweezers crunched
the perpetrator. It looked like a miniature crab. I do not recall
reading about any Candycane pests. I have this candy cane a couple
years. But recently I took in a large colony from someone since it was
deteriorating in his tank. Maybe it is infected with this pest. I have
not found any more yet. Right now the bright green center of the head
that had the crab does not look bright and is not very green. The mouth
is a large hole and is how many of the heads look in the colony that I
took in. Aside for keeping my eyes open for more of these creatures is
there anything I should do? Would it be useful to do a freshwater dip
to force out any more of these creatures? <Naw, don't do that.
It won't help and would probably just stress out the coral.> I
did not quarantine the sick Candycane because it came from a tank that
is much better than mine and my thought was that the other corals were
causing it to decline. <Well, quarantining has nothing to do with
how well the tank it came from is/was doing. But anyway'¦ very
few crabs reproduce readily in aquariums. So even if this
'crab' is a pest, if it's actually a crab, I wouldn't
worry about it multiplying. Also, you never know if the crab caused the
coral's problems or if it simply took advantage of the coral's
decline. Just keep an eye on the coral. If it doesn't recover, then
you might have to think more about why it's suffering.> Thanks
<De nada, Sara M.>
Added Crabs, Shrimp are Gone; Mithraculus 8/22/07
Hey gang! Boy, if anybody can mess something up it's me. <I bet
I'm worse.> I had/have an issue with Valonia (sp?) bubbles, it
was really severe. I decided against the raccoon butterfly because of
issues it might have with my inverts so I bought some small Mithrax
crabs.. <Ok> The Valonia bubbles are receding except for the big
ones I can snag with a siphon tube but what disturbs me is the sudden
disappearance/deaths of my shrimp. <Uh oh> In the past two weeks
(since introducing the crabs) I've lost two very large skunk shrimp
and one small peppermint shrimp. I took the deceased peppermint out, it
seemed to be intact. I only saw the carcass of one of my skunk shrimp
briefly this morning but it was gone before I could get it. No sign of
the other. <Dead things disappear very quickly in aquariums.>
Everything else in the tank (2 fire fish, 1 azure damsel, 1 royal
Gramma, 1 orchid Dottyback, and assorted corals that have been in the
tank since I started over a year ago plus one huge bubble tip anemone
and it's large clown) are fine. Is it safe to assume that the
Mithrax have killed the shrimp? <Definitely a possibility> I
wouldn't have expected it, I figured they'd feast on the
bubbles. <They eat whatever is in front of them.> Should I trap
and remove them? <Could> I have a large abalone I'd hate to
lose but I am seeing some empty snail shells as well. <Sounds like
the crabs may be your problem but hard to say for sure. If something
else is killing the shrimp and snails then the crabs may just be
cleaning up the leftovers.> Thanks for your kind assistance that you
generously offer. Lisa <If possible separate the crabs into the sump
if you have one or another tank and just move live rock in and out as
they eat the algae.> <Chris>
Re: Added crabs, shrimp are gone! 8/23/07 Thanks
Chris :) I'll set a trap tonight. I do have a refugium, it's
full of Chaetomorpha. I'll add some rock. <Sounds good.> I
watch the tank at night with a red light, the only thing I notice are
the crabs. I'll update when they're out. <Ok> Thanks so
much for all you do :) Lisa <Welcome> <Chris>
When In Doubt...(Potential Problem Crab) --
08/08/07 Scott, <Scott here, Captain...> Since I have
your attention . . . what's your best guess on an ID of the
attached crab and whether I should try to get him out of the
display? Looks to me like a Mithrax forceps. So far, he does not
"seem" to molest any of his tank mates. I will say,
however, that the dorsal fins of my Maroon Clown and Brown
Combtooth Blenny do sometimes have "chunks" taken out of
them (which quickly regenerate). Andy <Well, I'm not really
well versed on crustacean identification (that kinda rhymes, huh?),
so I would probably err on the side of conservatism and consider
removing the crab to a tank of his own where the potential to cause
trouble is not there. I've made the mistake of not following my
initial gut feeling about things like this in the past, and paid
the price later! It may very well be harmless, but my philosophy is
"when in doubt, take it out"! Best of luck! Regards,
Scott F.> |
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Shrimp vs. Crabs: Overcrowding/mixed species issues -
7/24/07 Hello, <Howdy> I have been puzzled over the last few
weeks and I am hoping you all can help. <Hope so!> I had a fire
shrimp and two cleaner shrimp in my tank and they seemed to be
thriving. Very active, the fire shrimp molted several times, and was a
brilliant red. <They really are beautiful shrimp> Well, about 2
weeks ago, one of the cleaner shrimp had died, or been killed, and my
sally lightfoot crab was eating it. <Sorry to hear that> I
figured just bad luck. <More likely a hungry crab> About 1 week
later, I added another <!> sally lightfoot <Houston, we have a
problem> and within two days the other cleaner shrimp was dead and
being eaten by the crab. <Yep, saw that one coming> I started to
be concerned, and took some water to the LFS to check it out, and
everything thing came back in great range (I'd list it all, but I
don't have the exact #'s with me)<Okay>. This morning I
awoke to my arrow crab <Yikes! There's an arrow crab in there
too?> and sally lightfoot eating the presumably dead fire shrimp.
Now these guys are <aren't(?)> the cheapest things in the
world, and I <I'm> wondering if I should buy another one, or
not, with the crabs in the tank? <Definitely not!> I have 2 sally
Lightfoots, 1 emerald crab, 1 arrow crab, electric blue hermit crab,
and a couple Cortez hermit crabs. Is it bad luck <It's more than
that> or are they praying <preying> on the shrimp when they
molt? <Possibly, but I'm guessing they just like shrimp.>
Tank is a 14 gallon bio cube, with a few small corals, 20 lbs of live
sand, and 14 pounds live rock. There are some mushroom colonies, a
small clown, and purple Pseudochromis. <I'm sorry for your
losses, but unfortunately, the issues here are: too many
different/incompatible shrimp/crab species, in too large a quantity, in
too small a tank. If you want to keep shrimp, I wouldn't put more
than a single specie in a 14g BioCube, and no crabs. Crabs in general
are not a good idea in mixed reef situations, much less in high
concentrations. Sally Lightfoots and arrows, in particular, are known
to kill small to medium fish and invertebrates -- pretty much anything
they can get hold of. Emerald/Mithrax crabs can go either way, IME.
Sometimes you get lucky, sometimes you don't. While it's
possible that the actual deaths of the various shrimp could have been
due to other factors (stress of overcrowding, starvation, etc),
it's most likely the crabs did the killing. I would decide on
keeping one or the other, and trap/return the rest. I would also
recommend reading the FAQ's, and info at WWM re:
keeping/compatibility issues for these species, and prior to any future
additions.
http://www.wetwebmedia.com/marine/inverts/arthropoda/shrimp/cleaner.htm
http://www.wetwebmedia.com/swcrabcomp.htm
http://www.wetwebmedia.com/arrowcrabfaqs.htm Good luck!-Lynn>
Re: Shrimp vs. Crabs: Overcrowding/mixed species
issues - 7/25/07 <Hello!> Wow, you guys/girls are awesome,
thanks for the information and the advice. <You're very welcome
and thank you for writing in! Although it's too late to save your
little shrimp, your shared experience could save others down the road!
-- Lynn>
Stone Crabs! - 7/18/07 <Hi Bridget!> I have
pulled 3 of these guys out of my tank in the past 6 months.
<Yikes!> Pet store ID'd the last one and advised an
elimination program. All research on the web tells how tasty they are.
<I've never had them, but I've heard that as well.> That
really is kinda useless. <Well, if you do indeed have the same
variety of "stone crab" that they use in the seafood
industry, you can try Googling its scientific name: Menippe mercenaria.
That's the problem with common names, though. One name can be used
for many species.> My biggest question is, are they really all that
bad? <Well, not if you want a crab tank! If you want a reef tank
with snails, etc, in it, then yep, I'm sorry but they're bad.
Crabs in the Menippe genus are Xanthid, or mud, crabs and have a bad
reputation for being destructive in reef tanks. Also, some Xanthids are
toxic, so just in case, don't let anyone eat those crabs!> If so
what's your best advise for removal? <Please see this link and
the post labeled 'Trapping in Displays':
http://www.wetwebmedia.com/marine/inverts/arthropoda/crabs/swcrabfaqs2.htm
> I do know I no longer have any hermit crabs and my yellow tang has
gone missing? <Hmmmm, not good.> Now have 3 fish in the 75, 2
true Perculas and one coral beauty. Thank you for your time
Bridget <You're very welcome, and good luck! -Lynn>
Re: Stone Crabs! Follow-up 7/19/07 <Hi again,
Bridget! Lynn here.> Well I found some pictures here
http://www.okeefes.org/Crabs/crab%20photos%20and%20scans.htm and this
guy <(Pilumnus sayi)> is definitely what I have and not the stone
crabs <(Menippe mercenaria)> *Pilumnus sayi* <Thanks! Pilumnus
sayi, sometimes called the hairy mud crab, or spineback hairy crab, has
those same robust claws as the yummy stone crabs (Menippe mercenaria)
but with lots of bristles! Unfortunately, it's still a Xanthid and
potential trouble down the road for a mixed reef tank.> Hubby is
being a grump and not wanting to remove these guys. <I can
understand that. As much trouble as they can cause for the other
inhabitants of your tank, they're still neat little creatures! Why
not set up a separate tank for them? It's a win-win!> Myself,
I'm more than concerned about the quantity and I'm wondering if
they might be reproducing or if they just came in with the live rock.
<Almost guaranteed that they came in with the rock. The juvenile
stages of crabs have a next to nil chance of surviving in the average
tank.> I don't see these guys. They're professional hiders,
<Yes indeed!> I'm only finding dead bodies. <Of snails,
etc, or the crabs themselves? If it's snails, etc, that's not
too surprising. If it's crab bodies, they could just be the shed
shells from when they molt.> Which makes me more concerned about
anyone else in the tank. <Understandable either way!> Tank is a
75 reef established 3 years, new live rock with oysters 6 months ago.
<Sounds like a nice tank to me!> Thank you for your time. Bridget
<You're most welcome, Bridget. I'd try to trap these guys
(see previous link on this) and set them up in a tank of their own.
Good luck! -Lynn >
Re: Stone Crabs! Follow-up: Mysterious losses -
7/19/07 <Hi Bridget!> These are definitely dead crab bodies.
I've had several crabs/shrimp that have molted and it's fairly
easy to tell the difference. <Yep, sorry about that. I figured you
probably already knew, but wanted to be sure.> I saw the last one
the night before hanging upside down on the rock and he was a pinkish
red color which told me he wasn't feeling good. Next morning he was
sitting on the bottom of the tank. I had to really fight to get him
loose. He'd latched onto some plants, and a rock, and wasn't
wanting to let go. <The loss of these little crabs may be a simple
matter of too much competition for food. By the way, if you have any
shrimp, have they been shedding normally? If not, you might want to
check the iodine level. Insufficiency here could explain some of the
other invert deaths as well.> I still have the whole body sitting
here in a jar in front of me so I can reference back as I'm
searching. My biggest concern was reproduction. <No worries there.
True crabs, such as yours, hatch into a planktonic zoea/larval stage
that, without special food/care, have very little chance of survival in
a tank. They drift along in the currents, and become part of the food
chain.> Now I'm going to set up the pickle jar tonight. After
doing the reading I started searching the tank for lost residents, 3
queen conch, 12 hermits, and about 20 odd ball snails, missing. Past 6
months or so yellow tang, purple fire fish and blenny have disappeared.
Crabs need to go.. huuummmm <Yep, that's a lot. If water
parameters and chemistry are/have all been fine, and there's been
no apparent disease/injury, and finally, there's been enough food
for all those inverts, then you have to consider predation. I'd
definitely put a trap out and see what you get. Just out of curiosity,
have you heard any popping or clicking sounds coming from the tank,
especially at night?> Reminds me, walked into the fish store and
told them I had crabs. You can imagine those poor young men trying to
keep a straight face. LOL <LOL!! They're probably still laughing
over that one! I know it'll keep me going for a while!> Thank
you Lynn for all your help Bridget <You're very welcome,
Bridget, and thanks for the laugh!>
Re: Stone Crabs! Follow-up 2: Mysterious losses -
7/19/07 <Hi Bridget!> No strange noises, but we turn off the
tank and go to bed. Will let you know. <Sounds good.> You've
been great. <Happy to help - I just wish I could have been more
so!> Water is good, corals, mushrooms and anemone are growing and
healthy happy. <Terrific!> Thanks so much Bridget <It was my
pleasure! Take care --Lynn>
Re: Stone Crabs! Follow-up 3 - 7/20/07 <Hi
Bridget!> Nothing this morning, will change location, feed less at
dinnertime and shrink the jar a little and try again. <Yep, trapping
can take some time/patience/luck. Using 'stinky' bait
(shrimp/squid/etc), should help.> Hubby seems to think that we may
have lost some of the crew with the spike from the new rock, it's a
good sized rock, 35lbs <Yowza! It's entirely possible,
especially if it wasn't cured. Even if it was, though, it still
would have caused some chemistry changes.> with 7 oysters on it,
<Neat> one tunicate that I adore, he's about 3" tall,
bright orange. <Pretty!> We got the oysters for added filtration,
and they are reproducing rather quickly. <Sounds like they're
happy!> It also came with some non photosynthetic stony coral on it,
it came with 3 polyps on it and now there's six of them.
<Nice!> Also have something that looks like it might be a baby
bubble tip. Except it has this long curly tongue kinda thing that hangs
out, when hungry. <I've got a dog that does that when he sees
ice cream.> Cream and pink colored about 3/4" around and
impossible to photograph through that thick glass. <Understandable,
that can be a challenge.> Will update again as soon as I have any
news <Please do!> Take care <You too, and have a great
weekend! --Lynn> Bridget
Please help!! Clown and Crab Interaction
7/13/07 Good Afternoon guys (and gals), <Hello> I have a 10
gallon FOWLR (&LS) set up with a Skilter skimmer, maxi-jet 600, and
very stable readings for two weeks straight after cycling for 5 weeks.
<Ok> Last night I added a false Perc and a sally (she was a throw
in from the person I bought my Perc from). After using the drip method
for acclimation I have noticed that my false stays on one side of the
tank and the sally roams free. <Not unusually for a clown, although
you want to watch him closely.> I think I noticed (could be
paranoia) the crab stalking my clown. <Possible> I think its
nothing more than paranoia but I am really getting worried about the
crab trying to attack my Perc. <Crabs eat whatever they can catch,
and Sallies have been know to catch small fish.> He is constantly
looking for her and it appears to be scaring my clown. I looked on
DFWMAS.org and I got differing answers....I am about 99% certain I have
nothing to fear but after reading up on my totally unexpected and
unprepared for sally it appears he wont be in my tank for long
regardless. <Probably the best move.> I guess my question is
whether or not I should be concerned with the sally eating my clown.
<Can happen, although not too often.> Other than looking totally
freaked out whenever the crab "appears" from the rocks he/she
is doing great and eating. I see no markings on (we'll go with her)
her and she is very active.. albeit on one side of the tank. Thank you
in advance for you help Phil Murphy <Welcome> <Chris>
Hitchhiker Crab Removal - 6/7/07 Hi Crew,
<Hi again, Debra!> I have found another crab hiding in my sun
corals. <!> I don't want to ID him, I've seen enough
of him to know I don't want him around, period. <Heehee,
does this one have beady eyes too?> But flushing him out
won't be as simple. The first one slipped into a small rock
which was easily removed and exposed to air. Once exposed to air,
within a few minutes he was out where I flicked him into the water
using a bamboo skewer and removed the rock. But exposing my sun
corals to air for any length of time to try and flush out this crab
would most likely cause them more harm than the pesky crab is
causing. If left alone at some point he will get too big to hide in
the sun coral and seek another home. Are we talking months or years
before Dennis the Menace becomes Ivan the Terrible? <Sorry, too
many factors to be able to make a call here.> Should I just
resolve the fact that there's not much I can do until it gets
bigger and go ahead and move my sun corals from quarantine into the
main tank? <I wouldn't. That's one of the great things
about having a QT (and good for you for using one!). If you want to
get rid of this guy, now's the time. If you wait until he's
in the display, he'll be even harder to catch. It could take
some serious aquascape rearranging, and frustration, to get him out
of there. Plus that, chances are that by the time you want him out,
he will have already done some damage. It's just not worth
it.> The main tank (20 gallon long) is still in the building
stage so there are only 2 other sun coral colonies, one Tubipora
musica and two cleaner shrimp (L. amboinensis). Fish additions are
still being researched <Love to hear that!> but currently I
have in mind one Royal Gramma and 2 Pajama Cardinals (or 1
cardinal). <Okay> Should I just plan my tank around the fact
I have a crab and set a trap nightly until he's caught?
<Again, I'd remove the crab now, while in quarantine. One
thing you could try is flushing it out with a turkey baster (with
the coral submerged). Remove the sun coral to a bucket with some
tank water (enough to cover). Using the turkey baster,
'swoosh' water directly at the little crab (underwater)
until he gives up and runs out. Just be sure to aim the blasts
below/between the polyps. It may take some doing, but it should
work. Sounds like you're already proficient with bamboo
skewers, so one of those might come in handy as well to prod him
out. If that doesn't work, see here for more information/ideas
on trapping:
http://www.wetwebmedia.com/marine/inverts/arthropoda/crabs/swcrabfaqs2.htm>
What should I be wary of adding to my tank because of the crab?
<Will no longer be a factor once he's removed, but crabs are
generally opportunistic - can go for just about anything.>
Having done some research on this site:
http://www.imv.uit.no/crustikon/Decapoda/Decapoda2/Species_index.htm,
which has a lot of pictures of various crustaceans, I think it
might be in the Xanthidae family based on the similarity of its
body shape. <Mmmm, yes, this group contains a lot of crabs that
can be a problem in a mixed tank.> Thank you again. Regards,
<You're very welcome and good luck! -Lynn> |
Hitchhiker Crab Removal - 6/7/07 Hi
...Lynn? <Yep, hi Debbie. What's up?> During feeding my
sun corals tonight I was able to flush out that little critter
using a bamboo skewer with the tip bent at 45 degrees.
<Heheee! You really are good with those skewers!> I
accidentally broke off one of his legs during removal and the one
you see fell off while it was walking around the container
(probably because of me). <Will grow back.> In case someone
else runs into the same thing, here's a picture of him with
one of his missing claws. <Appreciate it, and thanks for
including the dime for size reference.> Curious, is it in the
Xanthidae family... can you tell? <Sure does appear so to
me.> I'm not positive but I think both claws were
identical, pictured is the left claw. Although looking brownish
here it is actually more of a maroon color. Hopefully there will
be no more crabs on the coral, but back to quarantine to be sure.
<Good for you - keep your eyes peeled and a skewer handy!>
Thanks for all your help. Regards,
<You're very welcome! --Lynn>
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Re: Red Fromia star has hole in its head! Help! 4/4/07 Mich,
Thanks for the reply. <Welcome!> The star ended up dying.
<I'm sorry for your loss.> I believe it to either be an
acclimation issue OR the teddy bear crab. <Either are
possibilities.> I went back to the shop where I had acquired the
star and there was a star from the same batch that disintegrated also.
<Unfortunately this is not terribly surprising.> But, to my
horror, I caught the teddy bear crab eating my sand-sifting star the
next day! It ate a whole arm before I knew what was happening.
<Yikes! I would not recommend the sand-sifting star (Astropecten
spp.). These stars decimate your sand bed removing beneficial organisms
and typically starve after a few months in captivity.> Needless to
say I have removed the teddy bear crab from the tank. <Mmm,
hopefully to a suitable home and not an untimely demise.> I had
searched online about the teddy bear and various sites said it was reef
safe and a detritus eater so I thought it was safe, thanks for the info
that says otherwise....wish I would have known. <Not every source
hold equal value.> Hopefully the star will live and regenerate a new
arm. <It may.> Unfortunately, none of my corals are happy since
adding the sponges. The tank at the store that one of the sponges was
in was being cleaned when I bought it (water was really cloudy).
I'm starting to think that I introduced a lot of toxins since I had
to introduce that water into my tank. <Yikes!> I am going to do a
few water changes daily for the next few days to get any toxins out.
<Do watch this carefully. Dying sponges can really do a lot of
damage.> Green mushroom won't open up, gorgonian won't come
out and my torch is losing tentacles! <Ho buoy! Not good!>
I'm about to do a water change right now. <Good!> I changed
it yesterday and the gorgonian came out for a while. <You may need
to do several large changes here!> Wish me luck! <Good luck my
friend!> Thanks again for the info, <You are most welcome!
-Mich> Luis
Hermit's a tripod now??? 3/11/07 I have recently
noticed that one of my larger--actually the largest of my red tipped
hermits has lost many of his legs. <So the Vietnam was is raging in
your tank?> He currently only has his pinchers and one left leg. He
is unable to walk or climb. The only thing that he can do with
seemingly great difficulty is turn in a circle. <This is to be
expected with a Septa-plegic.> I have been hand placing food in
front of him for the past couple weeks to prevent him from starving.
<As long as he is eating it, and you can continue this, after a few
molts, the crab should start to grow new legs.> All of the other
hermits are fine. -----Is it normal for this to happen to this degree?
<It is never normal for inhabitants to start losing limbs. The Sally
Lightfoot that you mention below is a likely culprit. Actually, if you
have a refugium, or another fishless tank to put this one in, I would
do that. Eventually you will be E-mailing us wondering what ate your
fish. The answer will be the Sally Lightfoot.> My water parameters
are and have been in perfect or near perfect range for over a year. I
only have a couple of Damsels, Chromis, O. Clown, Sally Lightfoot,
snails, smaller hermits and corals in my tank. My biggest worry is that
I am only prolonging a horrible life of immobility! Is it possible that
he will regenerate his 3 lost legs? <Please see above.> Or have I
literally made him a "sitting duck"? Any thoughts would be
greatly appreciated!! <I hope this helps, Brandon.>
Marine crab reef safe? 3/6/07 This guy must
have come in as a hitchhiker a while back. I just noticed him
today, and as of yet I haven't had any fish come up missing. I
do have one millepora that has shown some recent tissue loss, but
I{ do not think it is him. Anyhow I know hairy generally means bad,
but I thought I would check. He is fairly large, I would say at
least 3/4" across possibly an inch. Thanks <Mmm, not
"reef safe" on much of a sliding scale... I would remove.
Bob Fenner> |
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Re: Broken heater & resulting contamination
(conclusion & Crust. ID) 2/27/07 <Hi Dave!> Well this
should be the last post on this subject. <Will miss...>
Everything is back to normal, short of the large Sarcophyton still
that has not opened its filter parts of the polyps yet, we have
seen one or two open but not the whole mass yet. <Give it time.
You will notice that they occasionally go through bouts of looking
lees-than-great. I don't worry unless they bleach or start to
deteriorate.> It seems to bring in its polyps in the evening and
stretching out like a hand then closing the fingers together again.
I see it do this for awhile then it opens its polyps up again
always seeming a bit bigger each time afterward. Is this how they
grow? <I'm sure I don't have a grasp yet of the
behaviour of Sarcophyton, but I know when to worry. Not yet.>
Totally different subject: Last weekend we had a fish jump from the
tank (missing cover replaced). <Dang.> When I went to feed in
the morning I noticed the trigger didn't come out to eat and I
searched and searched the tank (before finding the blue throat on
the ground dried up) PICTURE THIS :)... So we are missing the
5" blue throat trigger, in my wife an I's
<"I's"? ...you mean my? ;) > search we see this
crab come out of a hole in the live rock. Never seen him before,
and this live rock has been in several tanks in the house for at
least three years. My wife screams OH MY GOD THAT thing ate our
trigger !! <Mmm... not likely, though I would consider the
*possibility* that the crab may have startled the trigger into
jumping in the middle of the night by touching or even pinching
him.> Thank god I found the trigger and this cool lil guy
isn't to blame. LOL. He has been in a few tanks with many
varieties of animals over the last few years and hasn't
apparently caused trouble or even showed himself till now.
<Would keep my eyes peeled for any aggression on his part. There
are precious few crabs that AREN'T opportunistic omnivores.
They will eat whatever can't get away from them, and smells
yummy.> Can you ID it from this pic? <Sadly, I cannot. I will
run it through BobF for you...><<I can't make it out
either... are the tips of those claws dark? See WWM re Crab ID...
this is very likely a predaceous species... and though small, you
will have to make the call to isolate, or remove... BobF>> He
lives waaay back in that hole behind him and only came out as far
as that. Notice the skewer and frozen food cube for scale. He
wasn't bold enough to come all the way to the cube. Thanks in
advance, Dave <Welcome, and good -GrahamT> |
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Acro Crab? Reef Safe? Yep! 2/22/07 HI crew!!,
<Hi there! Mich here.> Good evening, last week I introduced
this Acropora into my system and found this little guy as a
hitchhiker. As far as I have read, asked around and researched, it
is an Acro crab and would be safe to leave it there, but wanted to
double check with the experts here in WWM. <It is an Acro crab
and is safe to leave. Enjoy your lucky addition!> Thanks in
advance. <You're welcome! -Mich> |
Re: Acro Crab? Reef Safe? Yep! 2/22/07 Thanks
for the fast response Mich, so he stays where he is. Cheers!
<Welcome! Keep him there! Regards, -Mich> Alfonso Garza |
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Problem with <true? or hermit, really> Crabs and
Overstocking -- 2/20/07 Help! <Hi Janet, Brenda here tonight>
I have been reading through your FAQ's and reading elsewhere and I
am not finding the answers to my question. Since November 2006 I have
had a 24 gallon Aqua Pod. All my parameters are within the required
limits. I do a weekly 4 gallon water change to keep my nitrates down. I
have 4 fish (yellow-tail damsel, 1 clarkii clownfish, and 2 percula
clownfish), there are snails and crabs, mushrooms, an anemone (the
clarkii loves it there), a sea urchin, a blue star fish, frogspawn
coral, feather duster, star polyp, Caulastrea, Galaxea coral, yellow
pagoda, Zoanthid, and 2 cleaner shrimps. <Oh my! You're way over
stocked. You will also see aggression between the percula and clarkii
clownfish as they mature. You shouldn't mix corals and anemones,
especially a nano tank. The Galaxea has sweeper tentacles that can
reach up to 12 inches, the frogspawn also has long tentacles and the
Caulastrea up to 2 inch tentacles. These tentacles will sting all your
corals and your invertebrates.> I had (and these have not survived)
a electric flame scallop, black sun coral, pearl bubble coral, brain
coral, and Fungia. <I'm not surprised.> I feed them 1X a day
~ I alternate every other day with the following Mysis shrimp, Cyclops
Eeze (originally for the black sun coral), and prime reef flake food.
About a month ago, I took out 10 crabs (I had 20) because they seem to
be eating other things in the tank besides the garbage. <It is
recommended to have 1 crab or less for every 10 gallons. I don't
recommend crabs with anemones.> Now they seem to be eating snails
<This is common they can also eat small fish, corals, and nip at
anemones.> and they look they are eating each other, too. <Have
not heard of this, could be the sweeper tentacles.> It, also, looks
they have multiplied. What do I do? <Decide what sort of tank you
want to keep, anemone or coral. If you choose coral, select those that
are not as aggressive. Please research compatibility and care before
your purchase.> Janet <Brenda>
Camposcia retusa... decorator crab, comp. 2/16/07 Hi Crew
<Angel> I have a question regarding the above. I have bought one,
I suppose it was a bit of an impulse buy as I wasn't planning on
getting one, <Mmm, you're learning...> I'd never heard of
one, but I saw it and was fascinated. The shop didn't give me the
Latin name but from pictures I have seen on the internet it is
definitely this one. It is approximately 10 cm in diameter from tip of
leg to tip of leg. <Yikes... Giganto!> So he is fairly large
compared to my other shrimp and hermits. So basically I have a tank set
up with fish, shrimp (dancing) and hermits (red ones) waiting for my
new and improved 700 L new Christmas present tank to cycle. <Wow!
Send your Santa my way!> It is a reef set up in that I have live
rock in it, 2 types of algae plants, under tank sump, skimmer (thinking
of getting an ozonizer to make the water crystal, but that is another
question for the future may be). Any way as I have told Bob F in a past
email, my LFS only gets small stocks of marine life and quarantines
them for about 6 weeks before selling them and I am very good friends
with him and the manager and know that all their stock is disease and
parasite free. <Mmm, just my usual cautionary note here re... Most
all stores, wholesalers even... can't actually promise such...
there is just too much going on... mixed nets, containers, staff... to
warrant that contamination hasn't occurred, that new livestock
coming/going haven't passed things on...> So I took the crab
home and very excitedly put it (Kev) straight into the new tank
(acclimatizing obviously). Kev is doing really well, but now that I
have seen him trundling around and realized how big he is, although
small claws, <...> I am worried about what damage he may do to my
fish and hermits when I put them in. My LFS friend said watch with
small fish and shrimp, but now I am worried what would be classed as
small relative to his size and eating habits. <Ah, yes> My
smallest fish at the minute is a young clown who is approximately 5 cm.
So at the moment I am holding back on transferring my buddies into the
new tank. <You are wise here> I know that in the aquarium world
you cannot be certain of anything, but I thought you probably know more
about their track record for compatibility than most. On a positive
note though the Caulerpa sp. I bought had some hitchhiker xenia on it
and so I have attached this to the rock and he hasn't demolished it
and only took a little, so maybe Kev is the caring type. <Or not
caring for Pulsing Soft Corals... as the present "menu
item"> Have had no replies on the chat forums so its over to
you! Thanks in advance Angela (WWM fan). Please let Bob know that his
book CMA is brill!! <Much good help with this tome. I would
definitely keep your eye on Kev... and a spot in a refugium to move
it/him too not if, but when he becomes too much of a tankmate sampler.
Bob Fenner>
Re: Camposcia retusa comp. 02/17/07 Hi Bob <Am everting my
lips in my best... well... semi-okay impersonation of MickJ...
"Angie..."> Thanks for the swift reply. <Welcome>
Would you say he is probably too big for the rest of my fish and crabs
who are in shells of about 4 cm? Give it to me straight, don't
spare my feelings! My largest fishes are: 12 cm blue Cheeked goby 12 cm
long Midas blenny 8 cm long Regal Tang I know that I can return him,
sad though I would be. But I don't want to be unfair to my other
fish friends. <Mmm... if it t'were me, I would return this
Decorator... Too likely to be heartbreaks down the line> What do you
mean by "Much good help with this one tome." <Oh, the
publisher, James Lawrence is a pet-fish and publishing genius... a
delight to work with him and the Microcosm crew> Angela in a
dilemma. <BobF, in a heat to get out and work on the garden walk/run
the dogs...>
Re: Camposcia retusa comp. 02/17/07 Thanks for
that, he will be going back to the shop tomorrow, but he will be in
good hands. <Ah, good> From Angela (named after Carly Simons
"Angie baby"). Night time here so off to bed. Good night from
rainy Manchester.. <Sleep tight... from nice/sunny (today) southern
California. BobF>
Emerald crab and cleaner shrimp - 09/01/06 Hello! <Hi
Christy, MacL here today.> Thank you for all of your help from the
past, present and future! <You are so kind and we all appreciate
it.> Three days ago I added an Emerald Crab to my 25 Gallon
saltwater tank, 1.022 spg, ammonia 0, nitrite 0. I bought him to
control my Bubble Algae. My current residents are a Scarlett Cleaner
Shrimp, 2 Blue-Green Chromis, 9 Purple Mushrooms, 2 Red Leg Hermit
Crabs, 8 Turbo Snails. Before I purchased the Emerald Crab, I
researched and came to the conclusion that large Emerald Crabs could
possibly pose a threat to small fish or crustaceans if it was hungry,
but most likely a small Emerald Crab would do no damage to the other
residents of my tank. <Unfortunately Christy, small ones grow to
large ones and to be honest I have seen them cause problems at all
sizes.> I haven't seen any sign of aggression between the shrimp
and crab. My shrimp molted last night, and I didn't notice his
antennas being any different earlier today, I'm not sure if I just
hadn't noticed or not, but now tonight.. I've noticed that all
of his antennas are considerably shorter than before, except for one
which is the same length. <It is definitely possible for something
to have occurred during the molt which caused the antenna length to
change.> I'm having a difficult time believing that my less than
one inch Emerald Crab could have done that. I also can't find one
of my Chromis anywhere! I'm now worried that I've got a little
green goblin in my tank! My question is could anything have happened to
my Shrimp's antennas other than the crab getting hold of him? While
molting, could he have lost his antenna length? <My philosophy on
this is pretty simple, if things were good before I add some creature
then I start having problems after I add them, then I usually take the
new creature out.> On a different note.. I have a question about my
shrimp's molting regularity. He molts almost every week the morning
after a water change. Is it bad to molt so regularly? <In my
experience he's molting way too frequently. Are you adding
supplements to the water like iodine? That can cause them to molt more
frequently. There is a great section on molting in general in shrimp on
site, I'd encourage you to take a look at it. MacL>
Crabs in my house 6/27/06 I live in Hampton, VA near a marsh,
and we have been having a lot of rain lately. Last week and today there
were a lot of crabs in my garage. Is there any way to keep them out of
the house? Judy <A row of small melted butter dishes? Actually,
installing a flexible guard under the garage doors setting edge is what
I would do. See Lowe's, Home Depot... re. Bob Fenner>
Re: Crabs in my house 6/27/06 Thanks for the tip. Actually, I
had thought of putting down some Old Bay and hot sauce! <Heeeee!
Tasty! BobF, with a bib on>
The tiniest crab?? ever inside a candy cane
coral 4/6/06 I just bought a white/extra gum green candy cane coral
and just noticed a small hole in the tissue and what appears to be a
very tiny crab in it (approx. 3mm) is this uncommon and a reason for
concern? I am a wee bit worried- how will i remove the crab if needed?
thank you, Russell Thomas <Common (though not often observed) and
not a problem... though semi-parasitic in nature, these two organisms
live together in the wild. Bob Fenner>
White spotted crabs
in trouble... just natural predatory beh. - 03/26/2006 Hello and
thank you so much for what you are doing! the life of my crab is in
your hands. <Actually yours... my keyboard is all I can touch
here> I have a 55 sw tank that is only 2 weeks old. We got our 2 big
, white spotted crabs along with 5 hardy fish(1 of them is in
quarantine now) <This tank is too new...> They have been very
happy at fist, crawling and exploring our tank happily, but not
spending any time together. With time though, Hulk (the bigger sized
crab) started to attack Harold (a bit smaller guy) periodically. If we
didn't feed him as often as he wanted he would attack him as if to
say: if you guys don't feed me now I am going to eat Harold.
<Will... not William, just will> I interfere when he attacks,
pulling him off the poor guy. Now, even after we added shells, Hulk was
still a bully, and Harold is now a recluse, refusing to eat, and
spending his time motionlessly perched on the very top of our LR
mountain. <Some symbology now!> And he used to climb the funniest
places, like our filter tube, and be very active. <And trying to
escape...> Now I checked our water and it is ammonia and nitrite
wise safe. However, our heater seems to be broken and the temperature
has soared to 81. Could this be the problem? <Not likely> I am
replacing the heater today and have it disconnected for now.
Unfortunately, Hulk has also attacked our only snail and she is
motionless, too... But it's breaking my heart that Harold is not
even eating and probably not going to molt, since he is nowhere near
the sand but instead, climbed the highest point in our tank as if to
beg: get me outta here! Please, any advice, tip, suggestion, anything
at all to save the poor guy? Angel. <... another tank, or trade in
the aggressor. Bob Fenner>
Re: White spotted crabs in trouble -- MURDER IN THE
TANK!!! 4/6/06 As an update...the smaller guy has almost killed the
bigger guy today. Ripped him in half, his guts are outside, <Ah... a
goner> chopped off his 3 legs, 4th fell off. We put him in
separately, we don't know if the injured crab will survive. <Not
likely> I don't have the heart to just pull him out so he is on
his own, with his favorite shell, slowly dying... Is there anything I
can do, any medicine to speed up healing, what do you recommend to do
at this point??? We are so sad. <Mmm, not to be... inevitable...
I'd monitor ammonia, nitrite... likely will be "totally"
consumed... and soon... if not already. Bob Fenner>
Mystery Crab 3/22/06 Hi, <Good Evening> First,
thanks for all the great info you provide. <No problem>
I've been reading through the frequently asked questions for
years now and find them very valuable. I finally have a question of
my own though. I just discovered this crab in my tank and
miraculously isolated from the tank and have him in a bucket. I am
wondering if there is anyone there that may be able to identify
this type of crab and determine whether it is harmful or not.
<It's really hard to narrow down to species, maybe someone
else can interject here. However I wouldn't leave him in your
tank. Inevitably many species will pick at corals or other inverts
at some time or another. Do you perhaps have a refugium to move him
to?> I appreciate any help you can give me. <Hope that helped
a bit. You can also read more here: http://www.wetwebmedia.com/marine/inverts/arthropoda/crabs/swcrabs.htm>
I hope I haven't left any valuable information out, but the
pictures will tell more than I can probably. Thanks for all the
help you've given me in the past in the FAQ's. -Brad
<Have a great one, Jen S.> |
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