Worm ID: Likely Synaptid Sea Cucumber -- 8/17/10
<Hello Jen, Lynn here today.>
Good day to you!
<Thank you, and you as well!>
I have an interesting worm that I can't seem to find an ID on.
<I see it and guess what? It's actually a variety of Sea Cucumber/Holothuroid, mostly likely in the family Synaptidae. These Cukes are mostly nocturnal, 'moppers'/deposit feeders that consume organic detritus or sponge secretions. They do best in large, mature systems but can be offered sinking pellets as a supplement to their diet. Rob Toonen recommends dropping a sinking shrimp pellet near the Cuke just before the lights go out, as this will give the pellet time to soften before the Cuke begins to actively feed. Regarding size, some Synaptids can get quite large (5-6 feet/1.5-1.8 meters), however, most seen in aquaria remain comparatively small. Overall, they're peaceful but can fall victim to roving hermits.>
I've checked your site and just about every way I can think of naming it through Google as well. Perhaps you can help?
<Yep, I haven't seen one of these neat little fellows in quite a while, so I'm more than happy to help!>
These worms were found in the live sand from a tank we recently purchased.
<Nice>
When we transported everything to our house, I noticed that these guys were resting on top of the sand in the buckets and figured they were dead. We got
everything set up and once done, these guys came back to life. They started to burrow in the sand and by the next day they had their mouths sticking out with almost tentacle-like appendages.
<Yep, what you're seeing are the feeding tentacles/appendages. Synaptid Cukes tend to feed either from a stationary position, reaching out from within a rock crevice or sediment burrow, or while actively moving around. Either way, they can move surprisingly fast when it comes to retracting back into their burrow/crevice or making a quick getaway.>
I've attached a few pics as well as a link to a video of what these guys look like. The close up photo isn't very well done.
<No worries, the combination of photos/video you supplied is enough to be able to offer that what you have is definitely a Cuke, and most likely a Synaptid. Besides, trust me, I've seen photos so blurry/small, that you could hardly distinguish the rocks from the subject at hand! What you sent is just fine.>
The big red arrow is pointing towards his mouth (lighter circle with two black appendages coming out. And the smaller arrows point to the tentacles surrounding its mouth.
<Thanks>
They seem like they just filter feed,
<Although there are filter-feeding Cukes, Synaptids are actually deposit feeders, grabbing bits of food from surrounding surfaces. The most obvious difference between the two involves the feeding tentacles (since many times that's all you can see). In lieu of a ring of relatively simple tentacles (like your individual has), those of filter-feeders generally appear elaborately branched, feathery, and delicate. The tentacles bring bits of captured food to the mouth by curling in on themselves, one at a time, then unfurling back into the water.>
..but their appearance almost makes me wonder if their tentacles resting on the sand bed and outreached
<Typical position>
..like they are at night could possibly be some sort of predatory worm?
<Nah, what you have is fairly harmless, even though it's a Cuke. Normally, when a hobbyist finds out they have a resident Sea Cucumber, the first thing that goes through their mind is the dreaded 'Cuke-nuke'. That's when a stressed or dying individual spews its innards and releases a toxin that can wipe out a system. Sea Apples are beautiful, but notorious for this. What you have on your side is the fact that Synaptids lack the potentially devastating Cuvierian tubules that other Cukes possess. That's not to say though that what you have is completely harmless. These Cukes likely have their own defense system that makes them taste bad (or otherwise discourages predation), and if you have quite a few, and they all die, you could have an issue with ammonia. One thing you might want to do (for right now, anyway) is to run some carbon just in case, mainly because there may be some die-off (and ammonia build-up) as a result of the move. Be sure to keep an eye on your water parameters and be ready to perform some water changes if/when necessary.>
Any insight on these guys would be greatly appreciated!
<For more information, please see the following links: http://www.wetwebmedia.com/seacukes.htm
http://www.advancedaquarist.com/issues/nov2002/invert.htm >
Thanks!
<You're very welcome!>
Jen
YouTube Video: http://www.youtube.com/watch?v=sf7S6p1PcBM
<Take care, Lynn Z>

Sea Cuke identification -- 2/23/10 Hello to whoever is kindly responding! <Howzit Joe?> My name is Joe and I'm a student at the Sound School of long island sound in New Haven CT, And I was wondering if you could help me identify this Cuke one of my friends purchased at his LFS (without researching! AHHHH) and placed in his reef tank. I hope this attached jpeg. can help though the quality isn't 100%. I'm also wondering if it's time to remove I'm from the tank, because he hasn't been acting or looking normal. He's in a 300 gallon with two giant clams a yellow tang some hermits and an infestation of tiny snails along with other less aggressive fish . He has a basic sump for a filter. The Cuke has slowed down a bit but it looks like he's just enjoying the local grub (the sand seems to be his size) but I've also noticed tons of tiny white worm-like critters all over his back that appear to be enjoying the Cuke as grub, and he's got a good mound of feces going. There's also a hermit crab who crawls on the Cukes back and starts to pick at it. I'm worried the Cuke might get a bit annoyed and excrete the infamous innards. There was also a recent alkalinity crash in the tank we can't explain too well. Thanks for your time Joe <Mmm, looks to be a Stichopodid... maybe Stichopus chloronotus... of moderate use/safety when small... Bob Fenner>

Urchin ID: Family Toxopneustidae -- 2/9/10
Hi,
<Hello Greg, Lynn here this evening.>
I just noticed this hitchhiker urchin a couple of days ago.
<What a beauty!>
I saw him again today during a water change, plucked off his 'decorations' and snapped a picture. I'm wondering if you could possibly ID him,
<I'll certainly try. It looks like a neat little urchin in the family Toxopneustidae. If it came from the waters of the Western Atlantic or Caribbean, it's probably a common species known as Lytechinus variegatus. Although the common name is the green urchin, color varies considerably. This species, along with at least one subspecies, ranges from North Carolina all the way down to Brazil, and is also found in Bermuda. Potential size (diameter) at maturity is ~4' with spines, ~3' without. These urchins are known for having numerous specially adapted tube feet called globiferous pedicellariae capable of envenomating you, so look, but do not touch! You can see the tube feet in your photo; they're the translucent, flexible structures interspersed among the spines. In addition to defense, the urchin uses these tube feet to cover itself, and hold in place, bits of shell, sea grass, debris, etc. As far as diet, these urchins apparently love sea grasses such as Thalassia, but are fairly omnivorous, eating algae as well as meatier fare. For more information, please see the following links:
http://www.wetwebmedia.com/urchinsii.htm
http://oceanica.cofc.edu/TRCH-Echinos/web_Urchins/page07.htm
http://www.thecephalopodpage.org/MarineInvertebrateZoology/Lytechinusvariegatus.html >
..but failing that, is this an urchin with which I need to be concerned? I have several different types of soft and hard coral in my tank.
<Well, I wouldn't touch/handle it, but other than that I wouldn't worry too much. The urchin will graze on algae and possibly go after some small sessile invertebrates, but your corals should be just fine. You could always offer the occasional meaty bit (shrimp, silverside, etc.) or seaweed/Nori sheet if the algal food supply starts to dwindle.>
Thanks!
<You're welcome. That's a beautiful little urchin!>
-Greg
<Take care, LynnZ>

Unknown Creature: Sea Cucumber -- 2/8/10
Hi everyone, I'm Mike in the UK.
<Hello Mike, I'm Lynn - near Seattle, Washington.>
I've had my first reef tank up and running for 20 weeks now and to much success.
<Great>
I use your site often when help and views are needed as I gradually learn on the lower end of a learning curve, and I find it excellent. The reason I'm writing is that I'm trying to identify a creature that came out for the first time yesterday where I was able to take a photo (of which I have attached).
<Neat!>
The creature used to live in some porous rock and I could hardly see it.
<That's fairly typical for these little creatures. They like to hide within rock crevices.>
At times it would produce feather-like tendrils at the end that protruded from the rock, so I assumed it was some sort of bristle worm that was a filter feeder.
<I can understand why you'd think that. Those feathery tendrils ('feeding tentacles') are indeed used for filtering bits of particulate matter out of the water column. The neat thing is that the tentacles work independently, instead of as a group. When one captures a bit of food, it curls in on itself, taking the food to the animal's mouth, then unfurls back into its original position. What you have is a neat little filter-feeding Holothuroid, or sea cucumber. The small projections you see around the body of the animal are tube feet. The Cuke uses them to secure itself within a hole/crevice, to pick up bits of shell, etc., for camouflage, and for locomotion. All in all, these are interesting and mostly harmless little creatures. The only real worry with Cukes is their potential for toxin release when threatened or dying (aka the dreaded 'Cuke nuke'). Some are more toxic than others and risk increases with large Cukes in small volumes of water. Thankfully, I don't think you have too much to worry about with this individual since it's so small. I would leave, and enjoy it. Please see the FAQ's at the following link for more information, particularly the one titled 'Anemone Id? Nope, It's A Cuke! 8/10/07': http://www.wetwebmedia.com/cukeidfaqs.htm >
However after seeing it this morning I'm not sure. It is approx. 2.5 cm long and 0.5 cm in diameter. It reminds me of a moth caterpillar.
<Me too. One thing I'd like to add that's completely unsolicited is that I noticed in your photo that you've got quite a growth of Caulerpa on your rocks. The stuff can be a challenge to control but it can be done. Please see the following links for more information re: http://www.wetwebmedia.com/caulerpaalg.htm
http://www.wetwebmedia.com/caulerpacomp.htm >
I look forward to your reply and thanks for a great and informative site.
<You're very welcome. Enjoy the Cuke! LynnZ>

Nudibranch or Cucumber? Nudibranch: Likely Tritoniid -- 9/22/09
Hello Crew!
<Hello, Tim!>
Can you identify this marine invertebrate for me please?
<I'll sure try!>
It was a hitchhiker on my liverock. I'm not sure if it's a Nudibranch or a cucumber.
<It looks like a neat little Nudibranch rather than a Cuke/Holothuroid but I can certainly understand the confusion. Both have species with similar body shapes and branched structures around the head/mouth. In the case of Holothuroids, those structures are actually branched oral tentacles used for feeding, and typically number anywhere from 10-30. In comparison, Nudibranchs have oral tentacles along with two 'antennae' called rhinophores. Both tentacles and rhinophores can range in appearance from simple to highly branched/ornate. I think what you have is a Nudibranch in the suborder Dendronotina, family Tritoniidae. Tritoniids feed on soft corals (especially Xenia), so if you have any in your system, I'd remove this little guy. If you'd like to pursue this ID further, please see the following link for a list of species in the above-mentioned family (each is a link with more information/photos): http://www.seaslugforum.net/specieslist.cfm
Start with the genera Marionia and Tritonia. The genus Marionopsis is also a possibility, but not listed (try a Google or other search engine). You might also want to check the family Bornellidae as well (at the above link). There are some similarities around the head but the structures ('cerata') running along either side (down the back) tend to be simpler in shape (less delicate and finely branched).>
Thank you for the help in advance,
<You're very welcome -- that's a neat little critter!>
Tim
<Take care, LynnZ>

Hitchhiker ID: Rock-Dwelling Sea Cucumber -- 6/17/09
Hi again,
<Hello Elfrieda, Lynn here today.>
Another puzzler for me....6 months into the set-up of my 24gal Aquapod w/ metal halide light. It appears to be some sort of worm perhaps???
<Actually, what you're seeing is the feeding apparatus of a rock-dwelling sea cucumber/Holothuroid. For more information, please start with the FAQ's titled 'Please help to ID: Sea Cucumber -- 6/1/09' and 'Anemone Id? Nope, It's A Cuke! 8/10/07', located at the following link: http://www.wetwebmedia.com/cukeidfaqs.htm . Please also note links within the two FAQ's.>
The second time I've seen it on the same rock....and the last picture is just before it disappeared.
<Nice photos!>
Thanks so very much for your time.
<You're very welcome>
Elfrieda
<Take care, LynnZ>

Re: Hitchhiker ID: Rock-Dwelling Sea Cucumber -- 6/17/09
<Hi Elfrieda>
Another look at this stranger....
<Neat!>
Its tentacles appear to be catching food and one by one are drawn into its 'mouth'.
<Good observations - that's exactly what it's doing!>
Thanks again,
<You're very welcome>
Elfrieda
<Take care, LynnZ>
<<A nice short video clip... that RMF doesn't know how to add to WWM...>>