FAQs on "Other" Freshwater
Crab species
FAQs
on FW Crabs by Species:
Halloween Crabs,
Panther
Crabs, Vampire Crabs (Geosesarma
Bicolor),
Related Articles:
Fresh to Brackish
Crabs, Freshwater
Crustaceans, Invertebrates for
Freshwater Aquariums by Neale Monks,
Forget Crawfish Pie,
Let's Make a Crawfish Tank! By Gage Harford
Related FAQs: Freshwater Crabs 1, & FAQs
on: FW Crab Identification,
FW Crab Behavior,
FW Crab Compatibility,
FW Crab Selection,
FW Crab Systems,
FW
Crab Feeding, FW Crab Disease,
FW Crab Reproduction,
Fresh to Brackish
Water Crabs,
FW Crustaceans 1,
FW Crustaceans 2,
Terrestrial Hermit Crabs, &
Marine: Hermit ID,
Hermit Behavior,
Hermit Compatibility,
Hermit Selection,
Hermit Systems,
Hermit Feeding,
Hermit Reproduction,
Hermit Disease/Health,
|
|
Red Claw Crab not Eating 12/29/19
Hello! Hardly anyone knows anything about red claw crabs, as I
cannot find any answers as to why my red claw crab has stopped
eating!
<Let's see if we can help.>
He is kept in brackish water conditions, has filtered water, and
water that is always about 74 degrees Fahrenheit.
<Right. Let's review first. By "brackish", how salty are we talking
about? The first thing you do when brackish water animals misbehave
is change the salinity. Many if not most come from places where the
salinity varies, so just making a change can have a positive effect.
But the bigger issue is that you need to be using a substantial
amount of salt, not the teaspoon per gallon amounts often mentioned.
I'd suggest one teaspoon per litre (i.e., a salt concentration of
about 6 gram/litre) to produce about one-sixth normal seawater
salinity. If that didn't do the trick, feel free to double that
amount, which would get you around one-third normal seawater
salinity. Either of these would be much closer to real world
situations for Perisesarma bidens. Next up, review air temperature.
23 C/74 F is very much towards the low end for a tropical animal,
and I'd crank the water heater up to 25 C/ 77 F. In cold conditions
tropical animals will slowly lose vigour, and loss of appetite is an
extremely common symptom of that. Death invariably follows soon
after, though it may take weeks to happen.>
He is able to climb to get air or be in water when he wants. I have
sand substrate. When I first got him, he would eat his food fine,
but now, he won’t eat at all. I noticed he wouldn’t eat, so I ended
up putting his food right in front of him, and he still won’t eat
that food.
<Loss of appetite in crabs is almost always a symptom of
environmental problems. Review as stated above.>
I don’t think he’s molting, because he’s been acting this way for
about 2 weeks and I was told molting should only take about a day.
<Correct, and moulting crabs tend to hide away. They do need a
source of iodine to moult successfully, for which purpose either
offer regular portions iodine-rich foods (Sushi Nori is ideal) or
else specific iodine-enriched crustacean foods sold for use in
marine aquaria.>
Also, I don’t think it’s a calcium problem, as I give him special
vitamins that help provide him calcium every 3 weeks. I’m really
worried about him, and I have no idea why he is not eating.
<Hope this helps. Cheers, Neale.>
Re: Red Claw Crab not Eating
1/1/2020
Thank you very much for this help! Right after I added more salt, he
molted the next day.
<Great!>
Does he absolutely need to eat his exoskeleton? If so, he is not
eating it.
<No, he doesn't need to eat it, but most crabs do, simply to recycle
the calcium. If he doesn't, that's fine, but do add some suitable
replacement, like a small shell-on prawn that he can pick apart and
consume. Failing that, just dusting whatever he likes to eat (fish
meat, banana, etc.) with crushed cuttlebone or even fragments of
edible snail shells (escargot) will have the same usefulness. Some
crab foods are calcium-enriched and may be good enough on their own,
but personally, I'd make a point of offering
extra calcium immediately after moulting. Cheers, Neale.>
Re: Red Claw Crab not Eating 1/11/20
I’d like to thank you for helping me with my red claw crab.
Unfortunately, he has passed away even after adding a proper amount
of salt and turning up the temperature, as he just did not eat at
all.
<I'm sorry to hear that.>
I don’t know the reason for his refusal to eat, but after taking
your advice, he seemed to have more energy and would actually
approach the food (but still didn’t eat it). Maybe he was sick?
<Indeed, or perhaps, he'd been away from salty water for too long.
These are tricky animals to keep well -- they need brackish water,
high humidity (cold or dry air quickly kills them), and food that
contains all the nutrients including iodine and calcium. So while
inexpensive in themselves, and not demanding in terms of space, they
are tricky.>
I don’t know, but I’m glad I found your website and got some help.
You are very knowledgeable about these creatures, and people who are
having trouble with their pet crabs are fortunate enough to be able
to contact you for help. Again, thank you very much.
<You are most welcome, and thanks for these kind words. Good luck
with your next pet! Cheers, Neale.>
Purple Matano Crab Breeding
7/26/17
Hello Wet Web Media Crew, I wanted to follow up and see about the
answers to my questions. Are you guys stumped like I am, or are you
trying to do some research of your own to better answer my questions?
<First I've seen of this question, to be honest!>
This is the first time I've waited so long for a response (having been a
week today), but I know these are advanced questions that I haven't been
able to find an easy answer to. That being said, take as much time as
you
need, just let me know what's going on, please. I might redesign the
system I'm planning to house them in if certain factors won't work out
or aren't necessary.
<Understood.>
*Details of the planned system* I'd like to set up a system for these
crabs using 6 or 7 ten gallon aquariums that will be flow-through (since
I'm not sure what determines their sex), but am concerned with issues
with such a
system. For example, seeing as I plan to put a thin layer (half inch,
maybe) of pool filter sand, a structure of rocks along the back and
coming forward about 1/3 of the length of the tank (the tanks will be
situated to provide maximum possible number of tanks with the "ends"
[side panels] in the front and back instead of how is typically thought
of), and a nice piece of driftwood front and center, I want to make sure
the crabs will be happy and not have any water quality issues. The other
key factor of this is the DIY PVC overflow with the water level only
being a third to half way to the top (with a lid) to allow the crabs to
exit the water if desired.
With such a low water level, I'm concerned with the feasibility of
pumping water to the first tank and having an operating DIY PVC overflow
to transfer that water to each of the other tanks as per the King of
DIY's video on the subject.
<I agree with your concerns here. Even strictly freshwater crabs run the
risk of clambering out of a tank if they can -- in the wild even
saltwater crabs will leave rock pools in search of new homes if they
feel confined or
stressed. So while your basic idea is fine, I'd be working around the
idea of either (a) a single tank per crab with a fully enclosed
filtration system; or (b) a large tank divided up with egg crate or
cichlid tank separator to keep individual crabs separate but allowing
for a free flow of water between the compartments. This latter is how I
kept multiple Mantis Shrimps and works extremely well if done right.>
I also plan to have the seventh 10 gallon (or a plastic tote of larger
volume) be the filtration unit for this rack. The overflows will
transfer water from the front of one tank to the back of the next, with
the water exiting and forming a sort of waterfall on the stack of river
stones I plan to purchase and place. The pump will use a similar
methodology, except pumping water from the back of the filtration unit
enclosure to the back of the first 10 gallon in the series, as the final
overflow (on the sixth aquarium) will simply overflow directly across
(or down, if I keep the filtration below the rack) to save on resources.
<You *will* need to find a way to keep the crabs from escaping.>
*Concerns I'm facing, and some of why I asked the questions I did last
week* If the crabs' sex isn't based on a factor such as conspecifics
(other crabs of the same species) that are in the same area and their
sex, but is
instead determined by temperature, genetics, or other such factors from
a young age or during the prime of development, such a flow-through
system is entirely unnecessary. I'm providing the flow-through since the
sex might be determined by conspecifics in the same "area" (or rack, as
the case may be in my tanks). Not sure what would happen with a crab
that is completely isolated as far as developing into a male or a
female, but that's not
something I want to test with these parental generation crabs.
<Have these crabs been bred in captivity? I'm finding very little about
Syntripsa spp. reproduction. Freshwater crabs have wildly varying modes
of reproduction, from the basic model (march to the sea/river, release
planktonic eggs and hope for the best) through to species that brood
their eggs like crayfish do, releasing miniature versions of themselves
only when the baby crabs are developed enough to fend for themselves.
Without knowing about Syntripsa reproduction, I think it's really
difficult to plan a tank specifically for their breeding. My guess would
be (as lake dwellers) that they either brood eggs or release relatively
large eggs that quickly hatch into baby crabs, rather than having a
prolonged planktonic stage, but I really have no idea. This is something
you'll have to research. Obviously rearing crabs with a planktonic phase
is hard. Sexing crabs is fairly easy though -- females tend to be
smaller and have a broad flap-like 'apron' under the body whereas the
males have a much narrower equivalent structure.>
*Conclusion* These are all answers I hope to answer with every type of
freshwater, brackish water, and saltwater crab I might keep in the
future (though I may stick with just the freshwater ones since there's
so many),
along with many other questions I'm coming up with as things progress.
The distinct lack of scientific info and inquiry on many crabs we keep
in the hobby are why I've chosen to do this and focus on truly
freshwater crabs
for the time being, possibly expanding into brackish water and saltwater
in the future as mentioned. I fall in love with the Purple Matano Crabs
I currently keep on a nearly daily basis, so the passion is there. I was
just hoping you could help me out with some of this seeing as I would
like to keep them properly, breed them successfully (to study the
crablets, as well as having a source of revenue in the future), and
ultimately further our knowledge base of these wonderful creatures. That
being said, I completely understand if you guys don't know or can't
answer certain parts of my questions. It's been difficult to find much
info on these questions, but that's why I ventured to ask you since you
guys are expert biologists from my understanding and I just have my
Bachelor's in Conservation Ecology (BS from Arizona State University,
2017).
<A good grounding for what you plan to do, no doubt. I'd be hitting
Google Scholar, finding out about Syntripsa spp. in terms of
reproduction; and where lacking, making comparisons with its close
relatives among the Parathelphusidae.>
Thank you once again. I hope you can provide some insight into the
challenging questions presented in my previous email that I've expanded
on in this one to follow up.
Best Regards, Jacob
<Good luck! Neale.>
Re: Purple Matano Crab Breeding 7/26/17
Neale, From my understanding, true freshwater crabs are those that have
the suppressed larval stage.
<Seems reasonable, but recall that many freshwater shrimps have a marine
larval stage. I think you would need to confirm the ecology of your
chose Syntripsa species before planning on breeding them.>
Such crabs ... as you mentioned ... have fully developed crablets hatch
out of the eggs. Others that march to the sea may be classified in a
family of land crabs while not being truly freshwater since they still
need some
fashion of saltwater to reproduce. I didn't know about the releasing of
eggs that hatch into crablets, though! I thought they all brooded the
eggs like crayfish.
<Since freshwater crabs evolved multiple times in many families, I'm
sure there's great variation. I simply don't know enough about this
group to be sure -- but as a zoologist, I'm minded to be skeptical of
any hard-and-fast
rules.>
I have tried the egg crate method of separation for these crabs in my
100 gallon. Unfortunately, as I was introducing them into the tank one
climbed through.
<Try tank dividers then; PennPlax make quite nice, easy to install ones.
If possible, combine with undergravel filtration because these do
restrict water flow, which undergravel filters bypass rather well.>
Several then followed suit (all except the largest could climb
through)...
I documented it in one of my YouTube videos. Once they get to breeding
size I might revisit it, but until then I'll likely just try to have
separate filtration with a mattenburg filter just behind the start of
the waterfall.
Should be interesting to find out what the two juveniles develop into.
<Understood.>
I hope I can figure out at what point to introduce the two crabs
together (male and female), as well as the technique I 'should' use so I
don't end up accidently killing the only female I know I have so far.
<I fear trial and error! But more realistically, large tanks might help
by reducing stocking density, as well as numerous hiding places so that
females can hide away when required. Ideally, if males/females very
different in size, burrows only the female can fit in. Much like
breeding aggressive cichlids, really.>
Would you recommend me looking into how others breed brackish and
saltwater crabs for such info on the technique of intensively breeding
crabs?
<Worth a shot! Crab farming is a thing, so you will find info online
about Mud Crabs (Scylla serrata) and other species farmed in tropical
Asia and Australia.>
Do you know anyone I can contact specifically, or do you possibly have
advice you can give me from your own experiences?
<I know of none personally, and I would imagine that with these new
aquarium species, any aquarist who knows about breeding them would be
extremely secretive about it! But you could certainly try the usual
forums like Planet Inverts and Pet Shrimps.>
These and related crabs have little info at all that has been studied
scientifically using the scientific method, and likewise I don't think
such crabs have been bred in captivity.
<Nor do I.>
I'll definitely do more research into these crabs, though. Thanks again!
Jacob
<Cheers, Neale.>
New tank setup and stocking questions... More study; rdg.
6/13/14
Hi crew I've just bought a 6 gallon Fluval edge that I
plan to setup on my desk but I'm uncertain of
how I want to stock it.
<Mmm; have you read here?:
http://wetwebmedia.com/FWSubWebIndex/stkgSmFWSysF.htm
It is going to be a planted tank with small
driftwood and Manzanita with eco complete
substrate. I was planning on just some shrimp and maybe Thai
Microcrabs.
<Mmm, the crabs will eat the shrimp; and each other if hungry>
Right now I'm leaning towards Sakura Fire Red shrimp and Thai Microcrabs
but I don't know quantities to prevent over stocking in a small tank or
if the water chemistry needs are compatible for those two species. I'm
also undecided on the species of shrimp. I want something colorful,
breeds easily, and is easier to care for so I'm open to
suggestions on the species of shrimp.
<... ? See WWM re... >
I'm also curious if the tank could handle adding CPD's or another small
fish bio and swim space wise with the shrimp and microcrabs but that's
just an idea for the moment. I'll have plenty of time to find out what
to stock it with waiting for it to cycle.
I also have a planted 60 gallon tank that I would like to change/add
stock in. It has 2 Raphael catfish, 1 golden algae eater, 4 kuhli
loaches, 1 German Blue Ram, 1 pearl gourami, 3 bamboo shrimp, 1
Farlowella, and 8
tiger barbs. Specs are temp 79-80, ph 7.5, kH 4, gH 3, nitrates less
than 20, and 0 nitrites or ammonia. When I set that tank up I only knew
basic needs to start a tank but I didn't look into compatibility
of the inhabitants.
<? Why are you writing instead of reading? Look up what you have, its
compatibility... >
I would like to add another German Blue Ram and maybe 2 electric blue
rams to the tank but I don't want to add to that tank unless I know
everything is compatible in water chemistry. I want to add more
shrimp but anything smaller than the bamboo shrimp I'm afraid
would be an expensive snack. I would like to
add a vampire shrimp to that tank but I'm not
sure what it needs for chemistry. I would also take any suggestions for
colorful or attractive fish I could add to liven up my aquarium.
<... reading. Bob Fenner>
Thanks your crew and site are always helpful
Coleton
New tank setup and stocking questions. Neale's go
6/14/14
Hi crew I've just bought a 6 gallon Fluval edge that I
plan to setup on my desk but I'm uncertain of how I want to stock it. It
is going to be a planted tank with small driftwood and Manzanita with
eco complete
substrate. I was planning on just some shrimp and maybe Thai Microcrabs.
Right now I'm leaning towards Sakura Fire Red shrimp and Thai Microcrabs
but I don't know quantities to prevent over stocking in a small tank or
if the water chemistry needs are compatible for those two species. I'm
also undecided on the species of shrimp. I want something colorful,
breeds easily, and is easier to care for so I'm open to suggestions on
the species of shrimp.
<Any of the Cherry Shrimp species, Neocaridina heteropoda, are obvious
choices. Lots of colour forms, including the famous red one but also
blue, green, orange and black. Indeed, Neocaridina generally seem easy
to breed.
Neocaridina palmata and Neocaridina zhangjiajiensis are easy too.
Caridina species like Caridina trifasciata are smaller and I think
generally more delicate and harder to breed (or even impossible if they
have a part-marine life cycle).>
I'm also curious if the tank could handle adding CPD's or another small
fish bio and swim space wise with the shrimp and microcrabs but that's
just an idea for the moment. I'll have plenty of time to find out what
to stock it with waiting for it to cycle.
<Sure.>
I also have a planted 60 gallon tank that I would like to
change/add stock in. It has 2 Raphael catfish, 1 golden algae
eater, 4 kuhli loaches, 1 German Blue Ram, 1 pearl gourami, 3 bamboo
shrimp, 1 Farlowella, and 8 tiger barbs. Specs are temp 79-80, ph 7.5,
kH 4, gH 3, nitrates less than 20, and 0 nitrites or ammonia. When I set
that tank up I only knew basic needs to start a tank but I didn't look
into compatibility of the inhabitants. I would like to add another
German Blue Ram and maybe 2 electric blue rams to the tank but I don't
want to add to that tank unless I know everything is compatible in water
chemistry.
<To be honest the Rams are going to need much warmer water than the
Farlowella, which are very delicate fish that need cool, fast-flowing
water with lots of oxygen. Bamboo Shrimps like much the same conditions
as the Farlowella. Golden Algae Eaters are a menace when mature, so do
review this species (Gyrinocheilus aymonieri) and act accordingly.>
I want to add more shrimp but anything smaller than the bamboo shrimp
I'm afraid would be an expensive snack.
<Indeed; the Striped Raphael are predators on all sorts of shelled
inverts, including snails, let alone shrimps.>
I would like to add a vampire shrimp to that tank but I'm not sure what
it needs for chemistry. I would also take any suggestions for colorful
or attractive fish I could add to liven up my aquarium.
<Keep reading before spending anymore money. Vampire
Shrimps, indeed, all Atyopsis species, are very demanding in the long
term. They are pretty much filter feeders, and while they can eat from
the substrate, inefficiently, they don't compete well with catfish.
They're also rather vulnerable at moulting not to mention sensitive to
medications like copper.>
Thanks your crew and site are always helpful
Coleton
<Most welcome and thanks for the kind words. Neale.>
Malawi Blue Crab (Potamonautes orbitospinus)
10/31/12
Hello. I found this interesting crab and want some info. How big do they
grow?
<Big; 15 cm/6 inches or wider across the shell.>
Do they go through a larval stage?
<For this species, unknown to me, but some other Potamonautes are known
to have a completely suppressed larval stage, i.e., the mother holds
onto the eggs until fully-formed "mini crabs" are released.>
How would I get these to breed?
<Probably impossible under home aquarium conditions; see below.>
How big of an aquarium would I need to house one male and one female?
<This species is reported to be extremely aggressive towards its own
kind, much like practically every other non-micro crab imported into the
hobby. So keeping more than one specimen is a risky venture.>
Are they fully aquatic?
<More or less, but they are notorious climbers and escape-artists. In
the wild they are somewhat amphibious, resting in burrows above the
waterline, but mostly feeding underwater.>
What water parameters should I keep them at? I heard any parameters
Malawi cichlids can be kept at, these can be kept at. Is this true?
<Yes.>
Lastly, what type of setup would you recommend for these crabs?
<A very, VERY secure aquarium, perhaps with a rocky island or two for
them to come out of the water if they want to.>
I want to breed these to supplement my income and for the occasional
treat (I've never had crab but my family loves crab and I want to try
some). I think these would be good to sale because they are big enough
to be eaten and they are relatively rare in the US and Canadian aquarium
trade.
<I'm not sure this species makes much sense for this sort of venture.
There are lots of other fish and shrimp species that can be bred at home
and make a decent profit when sold to retailers -- ask your local
retailer what he or she could sell profitably, and take if from there!
Dwarf Gouramis for example are a good fish species to try because the
farmed ones are so healthy, while some of the most popular shrimp
varieties like Crystal Red Shrimps still make a good price. As for
eating quality, do review carefully the literature here: home aquaria
are Salmonella incubators!>
Thank you for taking the time to answer my questions!
<Welcome, Neale.>
Re: Malawi Blue Crab (Potamonautes orbitospinus)
Thanks for responding so quickly. I did not know that part about
Salmonella. Thank you for telling me.
<No problem! Cheers, Neale.>
Goa land crab ID 8/21/11
Sir, I have found a crab in my garden it was crawling on the wall
and have problem finding its details on internet hope u will let
me know what type of species of crab this is bright pink colour
black eyes. is it a rare species or a common one. pls let me
know. I am from Goa India just happened to visit your site online
while looking for information.
regards. sample pics and clips attached
Elvis John D'souza
<I don't know this species. It's clearly a land crab
of some sort, perhaps a Gecarcinus species. But it isn't a
species I've seen in the aquarium trade so can't offer
you any better help than that. The zoology or ecology department
at your local or regional university should be able to help.
Alternatively, a local natural history museum or nature
conservation office. Cheers, Neale.>
Re: Elvis Goa India 8/21/11
thanks a lot
Elvis John D'souza
<Most welcome. Do read here: http://www.wetwebmedia.com/fwsubwebindex/fwcrabfaqs.htm
While crabs can make fun pets, they're mostly amphibious and
cannot be kept with fish or each other. Review Cardisoma armatum
online for the basics.
Cheers, Neale.>
|
|
Crab identification 11/17/10
Hello, I was wondering if you could help me identify a large crab
that I recently bought from Petco. They had it labeled as a
"Thai Red Devil Crab" but all my internet searching on
this name has not found any results. He is about 4 1/2 to 5
inches across with a purplish red shell. His left claw is much
bigger than his right, but not quite as much of a difference in
claw size as Fiddler crabs. On a side note, I was wondering if
crabs use their large claw for anything other than attracting the
ladies. Anyways, I currently have him in a 10-gallon semi
brackish tank (he will be upgraded to a 25 soon) with a cave to
hid in and one of those small turtle docks to allow him to get
out of the water. Is this setup ok or should I switch to a
terrarium? I also included some pictures of him and one of my
crayfish for your convenience. Any help would be appreciated.
Zach
<Hello Zach. You appear to have a male "Thai Devil
Crab". They're periodically traded but I have no idea
what their Latin name might be. In any case, they get quite
large, and they are notoriously aggressive and
predatory. They do appear to be more or less aquatic in the same
way as many other estuarine crab species -- i.e., by choice they
stay underwater, but that can venture onto land for short
periods. An arrangement of rocks above the waterline that allowed
the crab to bask under the light should it choose to would be
helpful, but otherwise don't worry about providing this beast
with a land area. Thai Devil Crabs don't seem to be
amphibious in the same way as Soapdish Crabs or Red-Claw Crabs.
One clue is their rather flat body compared to the much more
boxy, deeper body shape typical of amphibious and land crabs.
They do require brackish conditions though, SG 1.005 is ideal,
and I'd also recommend using marine aquarium Iodine
supplement at about 50% the recommend dosage. Although crabs are
carnivorous given the chance, their diet should be distinctly
mixed with plenty of green foods alongside meaty treats such as
tilapia fillet and unshelled prawns. As for differences in the
size of the claws, so far as I know this species has claws of
similar size, so your chap has probably lost a claw at some
point, and it'll be a few moults until the new claw matches
the other claw in size. Crabs do indeed use their claws for all
sorts of things, from signaling to one another through to
dismembering prey, snipping off vegetation, crushing snail
shells, climbing up things, and of course for nipping at anything
that attacks them. Crabs are fascinating animals, among the
Nature's success stories, and quite a sophisticated and
modern group of animals despite their sometimes archaic
appearance. Cheers, Neale.>
|
|
Re: Crab identification, salt 11/17/10
Hello again and thank you for the quick reply. I don't think
my crab lost his claw in a fight as all the other crabs in the
tank also had one large and one small claw. He also uses his
small claw to pick up food like
fiddler crabs. His large claw has roughly the same proportions to
his body as a fiddler but his small claw is a little bigger
proportionately. If both his claws were the same size as his left
I don't think he could move them. I'm sorry if you
didn't get the picture I will paste it to this message. As
for the salinity, should I use marine salt or is their a salt
specifically made for brackish water? Sorry if that sounds dumb I
don't know much about saltwater tanks.
Thanks in advance
Zach
<Hi Zach. The claw could easily have been damaged prior to
collection.
While it is not uncommon for crabs to have dissimilar sized claws
through accidents and fights, Fiddler crabs are exceptional in
having one claw massively overdeveloped as a signaling/fighting
tool rather than one for feeding and climbing. So far as I know,
crabs don't do the lobster thing of having one claw for
crushing and one claw for snipping. Yes: marine salt mix is what
you need, not "tonic" or "aquarium" salt used
for treating freshwater fish. Around nine grammes per litre
should be ample, with iodine added. Without the iodine, large
crustaceans are extremely prone to moulting problems in
captivity. Iodine-rich foods such as Sushi Nori make particularly
good supplements to their diet for the same reason. Cheers,
Neale.>
Re: Crab identification, sys 11/17/10
Hi sorry for so many questions (this is the last one) but how
long can these crabs live in freshwater? The salt in his tank is
"aquarium" salt. I might not be able to get marine salt
for a couple days will he be ok until then? I don't know how
long Petco had them in freshwater but he's been in my tank 5
days. Thanks.
Zach
<Hello Zach. "Aquarium" salt will do for a few
weeks, but in the longer term the lack of calcium salts as well
as iodine could cause problems. If you can, add 1 teaspoon baking
soda (sodium bicarbonate) and 1 tablespoon Epsom salt (magnesium
sulfate) per 10 litres alongside the aquarium salt.
These will provide some of the minerals crustaceans need for
their shells.
Also, add the iodine, either in the water, or through foods rich
in iodine (there are some special crab pellets available from
companies like JBL).
Cheers, Neale.>
crab compatibility 11/19/10
Hello, I would like to thank you again for all the info on my
Thai Devil Crab. I am going to get him some
marine salt this weekend. Anyway, my question is would a devil
crab be compatible with a Halloween
crab(Gecarcinus sp.)? I know crabs are aggressive but I figured
that since the devil crab is mainly aquatic and the Halloween
crab is mainly terrestrial they would pretty much ignore each
other. They would both be in a 55 gallon tank, (half water half
land) about 4 ft long and 1ft wide.
thanks
Zach
<Easy one this. No. These large crabs are extremely intolerant
of one another and in a small vivarium like yours cannot be
reliably kept together. When one crab moults, there's a good
chance the other one will
attack it. Cheers, Neale.>
|
Red Claw Crab Missing Limbs 10/12/10
I purchased 2 Red Claw Crabs from PetSmart.
<Perisesarma bidens'¦ and interesting, if aggressive,
brackish water crab.>
I believe one was male and one was female, do to the markings on their
underbellies, plus one had slim claws, and the other had fat, wide
claws.
<Do bear in mind males and females view each other as food except
when mating!>
After about a month, one crab (female) molted. She was seemingly fine
after the molt, with all appendages in tact. Two days later, 2 legs and
both front claws were missing. I removed the other crab (male),
assuming he attacked her. Three days later, the attacked crab died.
<As often happens.>
Am I correct in assuming the other crab attacked her?
<Possibly. When crabs moult they would normally hide in places such
as caves or bury themselves in leaf litter. Either way they'd be
out of view. Crabs view one another as potential meals, and in their
"soft" state they're easy targets. A lot depends on their
environment, and in a spacious tank with plenty of hiding places crabs
can moult successfully. But if you crab two crabs in 5 or 10 gallon
tank, it's hard for them to avoid each other, and if there
aren't any good hiding places, and I mean REALLY good hiding
places, not some upturned flowerpot, then they can, will attack one
another.>
Did the molt have anything to do with what happened here?
<Can certainly be a factor. But bear in mind lack of iodine is a
very common reason for failed moulting. Use marine aquarium iodine
supplement at 50% the quoted dose per gallon of water. Also make sure
their diet is calcium-rich -- a mix of whole lancefish, unshelled
shrimp, and suitable soft fruits should do the trick, along with
regular offerings of crustaceans foods such as those from JBL, Sera,
and others.>
Would the lost appendages result in her death?
<Not in themselves, no, but lack of iodine can cause various
problems, deformed appendages merely being the most obvious
symptom.>
Also, I've read on your site that RCC are land crabs, but mine
stayed in the water most of the time.
<Well, they are land animals. In the wild they live in estuaries,
dipping into brackish or salt water periodically but foraging on land.
On the other hand, for a variety of reasons they may prefer to stay
underwater in a given aquarium, perhaps because there's only enough
dry land for one dominant individual. Cold and dry air can also stress
them.>
My tank set-up: 10 gallon tank, part land, part water. Sea salt mixture
added to water,
<How much? You really need brackish water, not "teaspoon per
gallon" amounts of salt. Use marine aquarium salt at not less than
6 grammes per litre (~3.8 US gallons), and ideally 9 grammes/litre, for
a specific gravity of at least 1.003 and ideally 1.005 or more at 25
C.>
with calcium and other trace elements especially for invertebrates.
<Iodine is the key, and yes, you do need iodine supplement.>
Utilized a terrarium filter to clean the water. Fed spirulina flakes,
bloodworms, krill, and crab pellets. No heater was used in the
water.
<Well, that's one problem. They are tropical animals. The air
needs to warm and moist. Essentially you're creating a habitat
similar to what you would for tree frogs, except the bathing pool
contains brackish rather than fresh water. Apart from that, the coconut
fibre substrate will be similar, and the bogwood and plastic climbing
branches will be similar.>
After this experience, I do not believe PetSmart should be selling
these crabs.
<Difficult to argue against. But they are bizarre animals, and some
dedicated individuals have even bred them! The larvae need to be moved
into seawater conditions and fed tiny live foods, but it is
possible.>
They seem to be aggressive towards one another,
<As are virtually all crabs.>
and their requirements go way beyond what the pet store would have you
believe.
<Same with Goldfish, to be honest.>
I wouldn't recommend them as a pet for the average person.
<The huge problem is that the "average person" doesn't
usually keep pet animals terribly well. How many dogs do you know that
get short, infrequent walks? How many parrots do you know living in
small cages? How many Goldfish do you know get in bowls or small
aquaria? You and I are different in caring about how animals are
maintained in the home; the average person often doesn't care all
that much -- or perhaps more charitably, doesn't understand how
badly they're treating their pets.>
Thank you for any information you can give! Your website is
awesome!
<Kind of you to say so.>
Lorie Masi
<Cheers, Neale.>
Info On Mini Crabs <Micro Crabs> 6/11/09
Greetings,
<Elisa>
While I have learned much of what I know of the aquarium hobby from
your website, I am unable to find information on micro crabs (aka Thai
micro crabs, mini crabs, hairy mini crabs, scientific name possibly Limnopilos naiyanetri but I'm not sure on that).
From the little info I have been able to find on other sites, I am led
to believe that they are freshwater, don't need land, hang out in
plants, act like cherry shrimp, and like tropical temperatures -
I've read anywhere
between 64 Fahrenheit and 86....that's a pretty big range....
If someone knows about these adorable little guys, I would be ever-so
grateful if s/he would share that knowledge, or even direct me to a
legitimate informational site or book. Of course I would love to add
them
to one or more of my setups, but would never do that without first
learning about their water preferences, temperament, compatibility (it
seems they are more likely to be eaten by larger creatures than to
cause harm
themselves?), nutritional needs, etc.
<Limnopilos naiyanetri, has just been discovered by hobbyists in the
early 90's. About all I can tell you is that these crabs are found
in pure freshwater in the roots of floating vegetation, such as water
hyacinth and fine leaf plants along river banks. They have hairy bodies
and appendages which collect mud and dirt and may function to trap food
particles. They are not carnivorous, and behave like Caridina shrimps
in their scavenging behaviors, where care and feeding are probably the
same.
Googling will likely lead you to more information on the micro crabs. I
know of no book written on the subject and Bob and/or another crew
member may input here with additional info on the micro crab.>
Thanks in advance!
<You're welcome. James (Salty Dog)>
Elisa
Crabby Crab? Sabrina Has Crab Envy! - 09/03/2005
Just bought an apparently Yellow Moon crab from the local garden
centre. <Research prior to purchase, next
time.... I'm impressed, I suspect you have Geothelphusa
albogilva. This animal is currently unobtainable in the
US.> Guy said it was ok in my tank with 3 goldfish which are very
big. <Likely untrue.> Got the heater for him and the
right food etc. <Goldfish are coldwater, shouldn't
be heated.> He seems to want to get out of the tank all the time,
life seems one big struggle to climb to the top and spend some quality
time out of the water on top of the heater or filter
system. <Yup, this and all other crabs available in the
freshwater hobby absolutely require a land mass with hiding space -
these are land animals that spend some time in the
water. Geothelphusa albogilva is more terrestrial than
anything. At least the animal is actually
freshwater. I sure wish we got critters like that in the
hobby in the US.> Can't find any info on these crabs <Not
much out there, from a husbandry point of view - treat this like any
other terrestrial semi-aquatic crab.... Give it a large land
mass of several inches of sand and wood/leaf debris, with a great deal
of cover/hiding and a few gallons of clean, circulating freshwater.>
and worried I'm not looking after him right. Can you
give me any advice on making sure he has good quality of
life? <Just as above - this is an animal worth
accommodating.> Would really appreciate your help and comments.
<I'd absolutely LOVE some images of this animal.... please....
if you have time and a camera. I have crab envy.> Kind
regards, Joanna <Wishing you and your new decapod
well, -Sabrina>
Crabby Crab? Sabrina Has Crab Envy! - II
- 09/07/2005 God I feel so naive.....just thought I was buying a
funny cute looking crab to live next to my computer and look
nice. Guess I was major uninformed. <No
worries.... The fact that you are seeking information is
wonderful.> Didn't realize I had something unusual! Please
excuse my ignorance. <Again, no worries.> I am a total animal
lover and now dead worried this poor little creature is not getting the
right life. I will transfer him to another tank and somehow arrange
land for him to rest on and water when he needs it. How come I can
easily buy him here and you can't over there? <I have never
heard of Geothelphusa offered for sale anywhere.... But
Europe and the UK always tend to get "new" critters a few
years prior to the US. There are many shrimp and crabs
available in Europe that I'd do a great deal to get my hands
on! I suppose I shall just remain patient....> I will
take some pictures of him and send them to you... <Much
appreciated! I would very much like to see if this is in
fact the crab I think it is.> again excuse my ignorance as a first
time crab owner but what's the interest? He's not yellow or
looks like he's from the moon haha, just a small baby crab
that's whitish in colour and likes sitting on the
heater. <Once in a proper environment, I suspect
you'll find him much more interesting. The interest, to
me, is that I have quite a passion/fascination with invertebrates,
especially crabs and shrimp.... the interest with
Geothelphusa, to me, is that they don't or shouldn't require
saltwater access.... If there were more truely freshwater
land crabs available in the hobby, folks would be more easily able to
care for them properly, which is one of my main desires....> Guess
I'm entering a whole new dimension I didn't know existed out
there. <Invertebrates are really amazing animals!>
Would love to chat more, thanks for replying so quick.
<You bet. Sorry for the delay in this response; I've
been traveling a bit.> Where about in the US are you?
<In California.... In the Santa Cruz
mountains. Beautiful place.> I'm over in UK in
Yorkshire - God's Country. <Sounds excellent!> Best
regards, Joanna <Wishing you and your crabby pal
well, -Sabrina>
Amarinus lacustris, ID, habitat of a FW Crab from down
under 03/09/07 Can you tell me what "Myth" was
being referred to here in the question in the following
paragraphs? If I understand correctly the myth was
concerning Amarinus lacustris. I have been trying to get a few
specimens of Amarinus lacustris for a long time. I try to track
down every lead but this one is too cryptic for me to figure
out what was being referred to this time.. Michael Hissom Freshwater
Invertebrates, ID? Hey guys I am trying to ID a crab that is
appearing more and more frequently in Australian stores. It
has been incorrectly identified by several stores as
Amarinus lacustris (Freshwater spider crab). I suspect the
supplier is keeping this myth alive *lol Anyway, the crab in
question is often referred to as a "brown
backed crab". Orange/brown body with a chocolate brown
H symbol on its shell. claws of equal size and quite heavy
set, not long/slender. It seems to get to about
2" shell width. I would LOVE to know the scientific
name for this little beauty, as although I am sure I could
keep it happy using general crab knowledge, it would be nice
to know its specifics. Sincerely, Abbey AKA Callatya
<Mmm... well... this could be Amarinus... Please read here: http://www.google.com/search?q=Amarinus+lacustris&rls=com.microsoft:en-us:IE-Address&ie=UTF-8&oe=UTF-8&sourceid=ie7&rlz=1I7PCTA
... and am going to send your query to our resident FW crustacean
expert, SabrinaF for her input. Bob Fenner>
The Holy Soap Dish - 03/12/2004 My soap dish crab
recently molted about, three weeks ago. <A Cardisoma
species.... Perhaps Cardisoma armatum.> He has several
holes, or sores, in his pinchers. He seems healthy, but I have not seen
this before. Could this be a parasite or is there some deficiency in
his diet? Do you know what this is and how I might treat it? <The
likeliest thing that comes to mind is a deficiency in
iodine. Are you adding iodine to his water? I use
Kent marine iodine in my freshwater invert tanks, at a rate of ONE drop
per TEN gallons, once every week. I would imagine your crab
could/would like to have that increased a bit, though. The
second thing that comes to mind, this species, as well as many/most
other freshwater crabs, requires an area to get out of the
water. Without this, they may have health issues, perhaps
including what you are describing. If you don't have
such an area, please do consider adding something for
him. Even dropping the water level a bit and adding a
ramp/platform of cork bark in the back of the tank would do the
trick.> I have had this crab for over a year now and want to keep
the creature in good health. <Wonderful to hear.> Thank
you, Bob <Wishing you and your pinchy pal
well, -Sabrina>
Holy Soap Dish - II - 03/21/2004 Sabrina,
<That's me!> I will take your advice. Many thanks for your
help. There is not a lot of information about these crabs available.
<Agreed. I am SO glad you wrote back, I forgot to add the
link I had wanted to give you. Here's a listing of
(mostly) freshwater crabs (also shrimp, crayfish, snails, clams....),
auf Deutsch, but otherwise useful for identification - and if you can
read it, or translate via Google's language tools, there's lots
of valuable info there, too. So, without further ado,:
http://www.wirbellose.de/arten.html#Krabben
> It was nice of you to share your
expertise. Regards, Bob <Glad to have been of
service. Thanks for writing in! -Sabrina>
Mystery Crab - 04/06/2004 Hey
guys <Sabrina the freshwater crusty-freak here!>
I am trying to ID a crab that is appearing more and more frequently
in Australian stores. It has been incorrectly identified by several
stores as Amarinus lacustris (Freshwater spider crab). I suspect
the supplier is keeping this myth alive *lol <Yeah,
frankly, I'm still confused on that subject. Here's the
only photo/info I've been able to locate on the web about this
poorly documented little beast: http://www.nzfreshwater.org/crustacea.html
(scroll down) and
http://www.dlwc.nsw.gov.au/care/wetlands/facts/paa/plants/emergent.html
(scroll down to "Cotula coronopifolia -
Waterbuttons").> Anyway, the crab in question is
often referred to as a "brown backed crab". Orange/brown
body with a chocolate brown H symbol on its shell. claws of equal
size and quite heavy set, not long/slender. It seems to get to
about 2" shell width. <Any chance you can snap a pic
of this guy to aid in ID'ing him? The following two sources may
help you: http://www.wirbellose.de/arten.html#Krabben
and
http://www.wetwebmedia.com/marine/inverts/arthropoda/crabs/swcrabs.htm
> I would LOVE to know the scientific name for this little
beauty, <Me, too! I've looked through everything that
I have to look through, but without a picture to go off, it's
pretty tough to try to find a good ID. I would very much like to
see what your fellah looks like!> as although I am sure I
could keep it happy using general crab knowledge, it would be nice
to know its specifics. <Agreed. Always best to know what
your animals need - and crabs are pretty diverse.>
Sincerely, Abbey AKA Callatya <Hope to hear back.
-Sabrina> |
FW crab from down under info. Hi, This
isn't a question - I just happened across your website and
noticed a question someone asked about Amarinus lacustris - a
genuinely freshwater crab found in S.E. Australia. Here
is a photo if you are interested. Its about 6-7mm across
the carapace. Although I am no expert, I'm happy to
answer any queries anyone might have, although you were quite right
in your reply - there is little info available. It would
be illegal to attempt to export this animal. <Thank you for this
input. Will post on WWM. Bob Fenner> |
|
Crab Questions - 04/15/2004 Hello Crew-
<Hello, Jessica!> First of all, I wanted to tell you how
much I've learned from your website on the subject of my newly
purchased Sesarma bidens <<Now: Perisesarma bidens, Red Claw Crab>>! However, I do have a couple of questions for
you, and I know you can help. <Whew, you're a lot more
confidant than I am! But I'll try my best.> I have a
10gal. freshwater tank for the two crabs I purchased close to two
months ago. Both of the "girls", my 12 year-old son lovingly
named "Tara" & "Melissa", have been doing
wonderfully. They both have been eating well on a diet of algae pellets
and shrimp pellets. <So far, so good.> But, after
checking them both yesterday morning, and then later that afternoon, I
discovered "Melissa" was in a normal up-right position, but
wasn't moving at all. Maybe I'm being very ignorant and naive,
but I didn't want to throw her out until I knew for sure that she
wasn't actually dead and could be molting. <No, I
understand. Though, the molting process is usually relatively quick,
and they'll usually hide while they molt, and while their new shell
hardens.> I did check her this morning and there's still
no movement. I've spent the last three hours culling through
information about the crabs, but I've had no luck in finding
anything on what a dead crab will look like compared to a molting
crab. <At this point, if she's not moving, I would pretty
much suspect the worst. I am very sorry. It may have been aggression
from the other crab; this species, like quite a few others, are pretty
aggressive with one another.> We owned a very large hermit
crab for five years, so I am very familiar with molting. But I've
never owned crabs before. <They're pretty much the
same.... Though I would add iodine to the water (see our shrimp &
invert FAQs for details), and would certainly allow them a space where
they can get out onto a dry space somewhere in the aquarium; it is
quite crucial that they have a land space.> I also wanted to
ask about the actual necessity for salt in the water for these
crabs. <It is unnecessary. They may do somewhat better in
brackish water, and certainly need high-end brackish to breed, but
should do quite well in freshwater.> I found a ratio of
1tsp/10gal of kosher salt...it this a correct and safe figure to go
with, <Yes, certainly. You'll still be "fresh"
water, essentially. Even salt-sensitive fish can tolerate this
concentration.> and will it hurt goldfish if I choose to put
them in the water too? <The salt would certainly be fine for
the goldies - BUT - ten gallons is really far too small for goldfish. I
would recommend something simpler in terms of maintenance; goldfish are
really far too messy of waste producers to keep in such small confines.
How about mollies? These would do exceptionally well, you could keep a
few in a ten gallon with the crab, and bring up the salinity, even to
full saltwater, if you desired.> Thank you so much, and I hope
to hear from you soon. Jessica Linaweaver <You are quite
welcome; thank you for writing in. Please let us know if you have any
further questions! Wishing you and your crab well,
-Sabrina>
Molted Crab - 05/31/2004 I have a Red Claw Crab, he is
my first crab and I don't know what to do now that he has molted.
His old shell/skin is sitting at the bottom of my tank, I don't
know if I should remove the skin or leave it in the tank. <I would
leave it.><<Often are eaten,
reincorporated into new exoskeletons... necessary mineral content.
RMF>> I know Hermit crabs need their old
skin to eat, but I don't know what to do with this one. <If
it's not gone in a few days, pull it out. I would assume
the crab (or other denizens of the tank) will have made short work of
it, by then, but if not, best to get it out. Wishing you and
your crab well, -Sabrina> Shelly Warren
A Sesarma By Any Other Name.... Would Be A
Pseudosesarma 10/26/2004 Hi guys... <And
gals. Sabrina-the-freshwater-invert-freak at your
service.> We need your help. <Well, what d'y'know,
that's what we're here for! Hope to help you
out.> We have been getting conflicting information on our RCC.
<For our readers, that's "Red Claw/ed Crab", or as
you've mentioned in your subject line, Sesarma
bidens.... Actually, this animal is now thought to be more
accurately Pseudosesarma moeshi. Just a fun tidbit.> One
thing that everyone seems to agree on, is that RCCs are brilliant
escape artists. <True. Most (all?) crabs are.>
However, when we have been trying to research as to whether they
actually NEED to breathe air half of the answers are yes, the other
half are no. <Mm, not so much that they need to "breathe"
air (all land crabs use gills and require high humidity - even hermit
crabs, which carry a bit of ocean in their shell!), but yes, they
absolutely *require* a land mass to thrive. They will not
last long, forced to be fully submerged.... Or worse, fully
submerged in a freshwater aquarium, as they are unfortunately sold to
be. In addition to their need to get out of the water, they
also fare much better with some salt in the
water. Doesn't need to be much, but they do much better
with a bit of salinity.> Could you please set the record straight
for us? <Land mass required, yes. Most
definitely. It will live for a time fully submerged, but
will not thrive, and will not live long.> We don't want the
little guy to die, but we don't want him to escape either. <Any
chance you could drop the water level a few to several inches and offer
a good-sized land mass (even a very large piece of floating wood) with
lots of nooks and crannies to hide? This would likely be
sufficient. I suspect that the reason they are so renowned
for escaping is simply that they are desperate to find a way out of the
*water*, not the *aquarium*. All the same, a tight-fitting
lid is definitely called for. Do please try to accommodate
this animal rather than returning him; you will be greatly rewarded
with a fascinating pet, with just a little work. Perhaps
even a small, 10-gallon tank as a dedicated home for him and an
opposite-gender pal?> Thanks so much, <You betcha. I
really hope you choose to make this work out - these are fun
critters.> - Ian Fenn <Wishing you and your crab well,
-Sabrina>
A Sesarma By Any Other Name.... II -
10/30/2004 Hello again, Gurus of Aquaria! <Well hello!>
Thanks so much for your Red Clawed crab-help Sabrina. We finally found
someone/place that knows what they are talking about! <Heh, or at
least we *hope* we do! So glad to have been of service.>
We were wondering if we could please have some help with our cichlid
tank now. <Whups, not me.... I am cichlid-ignorant, for
the most part. Chuck, our mega-awesome cichlid master is in
possession of a duplicate email; hopefully he'll give you the
answers that you seek. I'll truncate this now, and give
you a big hearty "Thanks!" for all the kind
words. Wishing you
well, -Sabrina>
Anomalous Crab Question - 10/30/2004
Hello, My little red crabs keep getting on the filter and just sit
there like they are in a stream. <Er, do you know what kind of crabs
these are? Can you give me a good description of
them? Size, coloration, markings, anything like that?> I
do not see how they are getting up there unless they can swim. Why and
how do you think that they are doing this? <The how is the easy
part. Crabs are *amazing* for being able to climb nearly
anything.... I wouldn't be too terribly shocked if they
were simply climbing the glass! But more likely, they're
finding a way up to the filter intake tube, and climbing
that. Now, as for the "why" of it, there are
likely a few reasons. First, is this a fresh, brackish, or
saltwater aquarium? In what country do you
live? In the US, there are nearly - or absolutely - no crabs
sold in the hobby that are truly freshwater animals. Most
will survive in freshwater for a time, but they will not thrive and
will not live their full life span. Moreover, nearly - or
absolutely - no crabs sold in the trade in the US are truly
aquatic. All are amphibious, or land crabs that only
occasionally venture into the water. Chances are, your
little inverts are just trying to find a way out of the
water. At the very, very least, I recommend you drop the
water level a bit, and give them a surface to rest on out of the
water. Try to provide them with a few hidey-holes on the
surface to help them feel secure. Remember, crabs are
extremely adept escape artists, and they can and will find any way out
of the tank, especially if they're not happy with their
setup. Please be sure you have a tight-fitting lid, or you
might wake up in the morning to find a crab cuddling you in
bed! ;) > Thank you Kayce <Wishing you
well, -Sabrina>
Got Crabs? Hi WWM Crew! I have a 20g FW tank. In that tank I
have 4 guppies, 5 small goldfish (who will soon have there own tank),
and 2 small catfish. I was wondering, can I put some small red crabs in
there or will they harm my other fish. The ph is 7.2 and the
temperature is consequence at 73* F. Will this cause a problem at all?
Please, I would be very happy to hear from you. Thank you: ~Lena~
<Hi Lena, Don here. Sorry, can't recommend crabs. Although some
will thrive in FW, most would do better in at least brackish conditions
and all would need a place to get out once in a while. If they were to
catch a fish they would kill and eat it. There are plenty of FW shrimp
you could keep with the guppies and cats. BTW, You do need to move the
goldfish and then increase the temp to 78>
Thai devil Soapdish
crab I know this is not truly an aquatic species, so I don't
know if you can help. However, I thought that if
you didn't know the answer, you may know someone who
does. <Mmm, am actually one of those "guilty" ex-retailers
of yore who used to sell these w/o much knowledge of their
husbandry> My friend has a Thai Devil crab (Soap dish
crap). His large claw is inflamed at the joint
where it attaches to his body. He is in a 10
gallon tank, partially filled with water. He has land access
and spends most of his time there now. He is
still eating as normal and very active. The Ph of
the water is 7.0, but she does not have any salt added.
<IS a freshwater animal, that DOES eat various meaty foods>
He is fed a varied diet of krill and hermit crab
pellets. She soaks the krill in vitamins before
she feeds them to him. <Good> I understand that iodine
is important to these crabs. <A essential micro-nutrient for much
life, including you and I. I would add Lugol's solution, potassium
iodide/iodate once a week or so... to this animals water.> Does he
need special lighting? <No> And could the inflammation
be a sign of an impending molt? <Maybe> He is full
grown and they only molt once a year I think. She is
very concerned about his health, she has had him for about 6
months. Any information would be greatly appreciated.
Thanks, Caryn <I encourage you to place the above title words in
your computer search tools and read what little there is posted on the
Net re this crab/species. Bob Fenner>
FW Crabs Hello again. Thanks for taking a look at my letter.
I have a few more questions for you. Using the German crab ID page I
found on your site, I have determined that my soap dish crab is the
third Thai fresh water crab they have listed, it looks just like my
little Carl, right down to the dark zig-zags on his appendages. It says
it is of the Demanietta species, but that seems to include a lot of
different looking crabs. How can I narrow it down further? < Do a
Google search on the web using the Demanietta species you have already
found. That should get you closer to a correct ID.> Anyways,
I've started adding iodine to all my crab tanks. How often should I
add the drop? daily? < Add the drop of iodine every time you change
water.> The water I use is well-water with a softener. If this is no
good, what type of water should I use? Would adding some sea shells add
calcium to the water? < All crabs like brackish water. I would use
the softened well water but add some sea salt and micronutrients at
about 1/3 to 1/2 the dosage recommended for salt water.> I know the
fiddlers prefer brackish water, does Carl need some salinity also? <
You bet.> Should I change the water to brackish? < The sooner the
better.> Would his feeder minnows tolerate the salt? < They are
pretty tolerant to salt and would probably do OK.> He has not molted
since I have had him, but I just figured he was big enough that he only
molted once a year. Am I incorrect with this assumption? < Sounds
like a pretty safe assumption.> How big is this guy supposed to get,
anyway? What is this creatures lifespan? well, thanks in advance, Scott
< They usually get about 2 to three inches across the body and will
probably live between 2 and 5 years depending on how old Carl was when
he was caught.-Chuck>
Soapdish Crabs, Fiddlers, Ghost Shrimp hello: please, I was
wondering if y'all could help me. I have what was sold
to me as a Soapdish crab in a 2' x1' 6" tank with about 4
or 5 inches of fresh water. Carl, as he is called, has a
2" wide body and is probably about 6" across including
legs. he has relatively short (compared to my fiddler crabs)
eye stalks and is a reddish brown color with orange legs and claws that
have reddish brown "designs". the tips of
his claws are whitish gray. he has easy land access but
hardly ever comes out of the water. is that weird? <Mmm,
not necessarily> he eats live minnows and frozen
peas. anything else I could feed him for a little more
variety? <Other meaty foods> please don't say
crabs eat anything, he won't eat carrots or
broccoli. is it safe to feed him hot dog? <Mmm,
no... too fatty> he'll eat it and seems to like it
but I took it away because I'm wondering if it could be harmful
with all that sodium. should I remove any left over fish
parts from the water? <Yes, I would> sometimes he
just eats half a minnow and the other half just floats
around in the filter current. will it muck up the water or
make it unsafe for him in any way? <Could. I'd
remove all uneaten food> I have had him for probably 8 months and he
seems to be doing well. I just want to know if you
guys and girls have any tips to make him happier and/or
healthier. I read something on your site about iodine
supplementation for crustaceans? anything else? <You could monitor,
adjust biomineral (mainly calcium) and alkalinity... has this animal
molted while in your care?> what is krill, where do I get it and how
do I "soak it in vitamins"? <Euphausiids... liquid
vitamins... just putting a few drops on for ten, fifteen minutes before
offering...> I love my soap dish crab(s) and would really appreciate
any help y'all could give as there is virtually zip on the web
about them. also, for anyone wondering, Carl (as with all Soapdish
crabs, in my experience: I have 2 males, I lost a female when she
wondered into Carl's territory) is extremely aggressive and will
decimate anything it can catch, including other Soapdish crabs of equal
or greater size. does not play well with others. I've
even heard of one wasting an Oscar. <Have seen this sort, level of
"aggression"> oh, why might a fiddler crab in similar tank
conditions up and die for no obvious reason. <Is a brackish water
animal...> a not too old/big male that seemed to be thriving was
fine one day and upside down dead by the filter the next. he shares the
tank with 2 females and one other male which doesn't currently even
have its large claw. I don't suspect foul play, I am afraid there
is something wrong with the water or something. the tank has been in
operation for at least 6 months and has a good filter. I've heard a
terrible rumor about fiddler crabs just dying after a while in fresh
(not brackish) water but I've had a lot of these wonderful, mostly
peaceful crabs and this is a brand new occurrence. any
thoughts? might the same thing happen to Carl? <What is
the make-up of your source water? You may have hard, alkaline water
that "works" for both these species> just one more thing,
I promise. I employ a multitude of ghost shrimp as janitors and I read
on your website that it was easy to breed them. that is very exciting
to me, please tell me more! I am so glad I found your website, I hope
you can give me a few pointers. thanks, Scott <Use your computer
search tool/s... much written on Ghost Shrimp. Bob Fenner>
Re: Soapdish crab hello again! Carl has molted! about a week
after starting the iodine treatments, Carl (Thai freshwater- Soapdish
crab) molted. could this be directly related to the addition
of iodine? <Yes> unfortunately, it did not go well for
the big guy and he lost a leg and his larger pincher. <Evidence of?
Likely a lack of biomineral (calcium) and alkalinity... provided in
foods, water...> the next couple days were very tough for both of
us, as he just sat there and twitched and I was terrified that he
wasn't going to make it. the next day I came home from
work to find him on his back and motionless. I nearly lost
my mind with grief until I noticed his mouth apparatus was moving. I
very gently touched the tip of his claw and to my great relief he
sprung to life, trying desperately to flip over. the poor
guy just didn't have the strength! he was still very soft, so I
decided to let him be rather than possibly injuring him by flipping him
over. after a couple more days he eventually started to
consume his exoskeleton and move around the tank. Carl's
gonna be ok! whew! now for the questions: I've noticed
that since the molt his carapace and claw look very strange- its a very
dull tan-gray and none of his normal patterns, like the
"H" on his back, are visible. it just looks very
worn, or something. I know crabs will sometimes come out of a molt a
different color, but the way Carl's shell looks makes me think its
related to his traumatic molt. any ideas? <Either lack of nutrition,
water quality... or will develop color, pattern in time> Also, is it
possible to over dose them on iodine? <Oh yes> should I add the
drop only when I do a complete water change or anytime I replace water
that has evaporated? <Best to do with (weekly) water change
regimens> keep in mind I have a 10 gallon filter in about 4 gallons
of water, does that make a difference as to how fast the iodine is
getting used up? <Yes> One more thing: I really want to change my
crab tanks to brackish but I have read that once crabs are in
freshwater for so long, they cannot be switched to brackish. is this
true? <Not so. Bob Fenner> thank you in advance. Scott
Injured Red Claw Crab Hi, firstly thanks for such a great
website! The information here is comprehensive yet easy to understand.
Unfortunately I have a problem with my Sesarma bidens crab. The other
night whilst cleaning out the tank I did not notice the crab (Colin)
burrowed under a plant, as he is almost always hiding under an ornament
on the other side of the tank during the day (or breathing sitting out
of the water on top of it). He just recently molted (about a week
ago) so I thought I would leave him under the rock and clean the tank
around him. Well I dumped the plant in a bucket (with Colin underneath
it) and proceeded to vacuum out the gravel and remove other ornaments
to the bucket. It was only when putting the ornaments back that I
noticed Colin at the bottom of the bucket on his back... I immediately
picked him up and put him in the tank but he didn't move, I put
lots of little bits of food in front of him and left him for the night
thinking the worst. When I came back in the morning he was on his
back again but when I went to lift him out of the tank assuming he was
dead he started moving his legs frantically, anyway I righted him but
noticed that 5 of his legs were not working as well as one claw (I
think they must have been broken in the accident) he was attempting to
move around but the legs were preventing him, I left him for the day
came back and he still had not moved despite attempting to with his
working legs, so I amputated 3 of the legs at the base (not the claw)
he is now a lot more mobile however he is unbalanced due to missing 2
back legs (resulting in him overturning and not being able to right
himself frequently/a few times a day). I have also since noticed
that one side of his mouth is not working (i.e. the exterior movable
parts of his mouth that he uses to clean his eyes) he can still move it
a little but cannot properly function. My question is: Is there
anything I can do for Colin? I am aware that crabs can regenerate limbs
during a molt but has he just sustained too much damage? <I hope
not> My main concern is his mouth as I cannot see whether he is
eating properly. Would it be kinder to just kill him now or try to aid
his recovery? <I would not euthanize this animal. It may well
recover> It has been three days since the accident and he is still
defending his food against the fish (a few platies) but I cannot
establish if he is eating the food or whether the platies are
eventually managing to take it all. In this situation could a premature
molt occur or could he partially grow back before a molt? <Not
before, but might molt again sooner, shrink in body size> I really
don't want to have to kill him but equally I do not want to prolong
his life if he is suffering with very little chance of recovery. He is
in a 5 gallon tank with 0 ammonia, 0 nitrites, 20ppm nitrate, just over
1 tbsp. of salt per gallon and I am lifting him out of the tank daily
for a few minutes to allow him access to air. pH is 6.6 (low I know but
I added dolomite to the filter on the day of to raise it so hopefully
that will start to take effect). Should I dose with Iodine? <Yes, I
would> Sorry for the long question but I am very concerned about
him. Thanks, Chris <Do take care to maintain good, consistent
water quality, assure this animal is getting food. Could take weeks to
a few months, but may well be fine. Bob Fenner>
Freshwater
Invertebrates, ID? Hey guys I am trying to ID a crab that is
appearing more and more frequently in Australian stores. It has been
incorrectly identified by several stores as Amarinus lacustris
(Freshwater spider crab). I suspect the supplier is keeping this myth
alive *lol Anyway, the crab in question is often referred to as a
"brown backed crab". Orange/brown body with a chocolate brown
H symbol on its shell. claws of equal size and quite heavy set, not
long/slender. It seems to get to about 2" shell width. I would
LOVE to know the scientific name for this little beauty, as although I
am sure I could keep it happy using general crab knowledge, it would be
nice to know its specifics. Sincerely, Abbey AKA Callatya <Hey
there, sorry it took me forever! http://www.fishprofiles.net/files/~adam/tanks.htm
Right down the bottom of that page is a front-on view of that crab. I
asked a large pet store and they said they are buying them under the
name Holthuisana agassizi. I cannot for the life of me find any
reference to this species online, so I thought maybe, just maybe, you
guys might have more references that I have access too. Thanks for your
help! < I have seen this crab at wholesalers referred to as
"red clawed crabs" from Asia. Try looking in the internet
under that name to see if you can find more info. -Chuck>
Red Claw Crab <Hi Anthony, MacL here. The only red claw
crab I know of is actually a brackish crab often sold for freshwater.
Is this what you have?> I purchased a red claw crab from a local
Fish store about 2 weeks ago. I believe the crab is a female due to the
very small claws. Anyway, recently she has had her abdomen
hanging open. <Maybe releasing eggs?> I figure she was getting
ready to molt, but she hasn't done anything for 2 days now. She has
already molted once since we have had her and it didn't take
long. She has plenty of different kinds of
food. Also these past 2 days she is flipping herself over on
her back. <Not a really good sign.> Can you tell me
what is wrong? <I'm just guessing here but I think you probably
have her in fresh water and she needs some salt. I also think it might
be a difference in PH as well.> I have searched through
the internet, but cannot find any information on Red Claw
Crabs. <I did a search on Google and came up with tons of
thing on them. You might try www.google.com> Thank you
for your time and patience. <Anthony you might do the research on
them and decide if it needs to be in brackish water or not and make a
decision from there.> Anthony <An excellent site re this species:
http://wrongcrowd.com/aquaria/crab/
RMF>
|
|