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FAQs about Sea Cucumber Reproduction, Regeneration

Related Articles: Sea Cucumber, Marine Scavengers, Sand Sifters

Related FAQs: Sea Cucumbers 1Sea Cucumbers 2 Cuke IDs, Cuke Behavior, Cuke Compatibility, Cuke Selection, Cuke Systems, Cuke Feeding, Cuke Disease,

If "something" should happen... and your Cuke is in pieces... the larger ones may regenerate. Arothron mappa

Colochirus robustus dropped a part of itself  2/10/11
Good evening "crew". I have a 20 gallon reef tank
<Hard to keep such small systems stable>
with a MarineLand Emperor 400 filter and a SeaClone 100 skimmer. One of the inhabitants is a knobby yellow cucumber (Colochirus robustus from what I can tell). I have had him for 6 weeks. His feeding tentacle things are usually out. When they aren't, it is usually only for a short time. When I first got him he hung out on the rock that my finger leather is mounted on. A few weeks after I got him I moved all into a new tank. At first he hung out on the gravel looking all shriveled up. I moved him
<Don't do this>
to a higher rock with greater water flow. He moved to the filter sponge on the intake of my protein skimmer. Three days ago I needed to do maintenance on the skimmer, so I gently detached him
from the sponge and put him on a rock with some mushrooms and Zoas.
<Toxic... see WWM re compatibility>
He is under the return water from the filter. He has moved a little on the rock and is now in the middle of the Zoas. The feeding tentacles have not been out since the move, but tonight, at feeding, he lifted his head.
Two days ago, I noticed that one of the "knobs" on his side was extending.
It stretched and the part closest to the body narrowed over two days (like tearing a piece off of a caramel) and about an hour ago a small piece of the cucumber fell off. I have read about these guys reproducing by fission.
<Ahh, no; not of this nature>
I don't think that is what this is because it is not two ends; it is a very small piece off the side. Do you have any idea what is happening here?
<Poisoned, chemically burned likely>
Should I try moving him or just let him find his own way to a happier place?
With such a small tank (good filtration and skimming), am I risking the entire system by having this guy in my tank?
<Not especially, no. See WWM re this species husbandry>
I would like to add seahorses eventually.
Thank you.
<Do learn to/use the search tool, indices on WWM. Bob Fenner>
Re: Colochirus robustus dropped a part of itself   2/10/11

Thank you, I will move him.
Before I wrote last night, I spent 4 hours reading the article and FAQ pages, using the highlight and Google tools. Almost all of the questions about this species were answered that what the questioner was witnessing was reproduction by fission.
<Fission... as in bilateral... What you described was a form/type of schizogyny... partial splitting. Do read re>
I cannot find warnings about cucumbers and Zoas or a compatibility chart, only other comments about not being able to find the chart.
Thanks again.
<... not perhaps in particular, but here:

I responded to two days back. Please send a well-resolved photo. B
re: Is My Sea Hare Under Attack?  11/10/10
I sent this the other day and hadn't heard anything back yet. Just checking in...
Evening all! Tonight I saw my sea hare "Shrek" crawling by and noticed a rather large (approx 2") white "worm" near the side of his head. The "worm" had a small purple and orange marking on it's tail and it was about 1/8" thick (fatter than spaghetti). I attempted to remove it, but it seemed rather attached and after a second attempt, Shrek became stressed and released some purple ink. He then crawled behind some rocks and I was unable (as of now) to get a photo. Earlier today, the worm was not on him,
so I'm wondering if he picked up something from within the live rock. I'm paranoid. I'd be devastated if Shrek was being harmed by this creature and have searched the web for the last few hours trying to find info as to what it may be and what I should do. Your suggestions would be greatly appreciated.
<Mmm, could you send a well-resolved image along? Bob Fenner>
Is My Sea Hare Under Attack?  11/10/10
After doing MORE research on Sea Hares and their anatomy, and the death of Shrek, I was able to conclude that this "white worm" thing was, in fact, the Sea Hare penis.
(Yay me, for trying to remove it. Duh).
However, I also discovered that when this happens, it is a sign that the Sea Hare is sick. True, because Shrek died yesterday. I'm still not sure what caused his death because he was eating and moving about up until yesterday, although my husband said he noticed Shrek seemed a bit smaller than normal.
<Sea cucumbers, all echinoderms can/do shrink down in size under adverse conditions>
Anyway, hopefully this will be some information that someone else may be able to use in the future... I've been worried and researching for days now trying to find answers to my questions, only to wind up finding out that he was sick and now dead. Despite my utter ignorance of thinking this was a parasite, it's also rather embarrassing when you come right down to it.
Anyway, if anyone else out there sees a long, white worm-looking thing hanging off the side of their Sea Hare's head on the right side, it's probably the sea hare penis and your sea hare is probably sick.
<Thank you for sharing. BobF>


Indonesian Sea Apple   8/15/07 Hey guys, love the website and the information you so kindly provide. With that said, I work at my LFS and have been working in aquaria for about 4 years. I purchased an Indonesian Sea Apple for my 30-gallon community tank, <... Yikes...> knowing (or at least thinking I did) the inherent risks of the organism. I have had the Cuke for more than 4 months and he receives daily doses of Marine Snow <Of almost no nutritive value> and has appeared to be doing well (no inflating from stress, no loss of size, no moving in the tank once established). Today however I came home and noticed that one of my favorite fish had passed, one of the ones I had had in the tank for a while (5-6 months). I peered into the tank and noticed what appeared to be little green balls (about the size of a flea perhaps?) floating all around in the water. I examined the Cuke closely and it appeared to have strings of these little balls wrapped around a few of its feeding feathers. Another reader had written you about a similar experience ("little yellow balls" in his case) and I was wondering if this is in fact the Cuke reproducing? <Possibly this... or fecal material... or?> I couldn't find any info on how they reproduce. Is it common for them to reproduce in captivity? <Not uncommon> Also, if so are the eggs simply themselves toxic? <Can be, yes> I have never done a full change on my tank and unless I notice labored breathing or anything of the like I don't intend to, at least until I establish that this did in fact come from the Sea Apple. <Good point... this material could be unrelated to the Holothuroid> Aside from him the only other inverts in the tank are a pair of Skunkback Cleaner Shrimp and Peppermint Shrimp, <Could be their eggs... though unusual to be released as such> Margarita Snails, Blue-legged hermit crabs and a small Tiger-Tail Cuke and of course the corals (mostly Euphyllia, Toadstools, Zoos and Mushrooms). Thank you for any insight into this odd situation! Alec Parodi Valencia, CA <Do keep a close watch on this system... "If" something goes sideways with the Sea Apple... all could turn into bouillabaisse in minutes... Bob Fenner>

Re: Indonesian Sea Apple   8/15/07 PS - Somehow missed the section on your site with the information about the sea cucumber reproduction. I now see that this is exactly what happened. Despite my cautions with it dying being a problem, I never thought that it THRIVING (i.e. reproducing) would be a problem. In the last 2 months though I have had my rose bubble anemone split once and my toadstool leather reproduce through self-fragmentation a total of 12 times. Guess I am taking TOO good of care of my tank. Alec Parodi Valencia CA <Heee! Possibly. BobF>

Re: Indonesian Sea Apple 8/15/07 Thank you very much for the reply and information Mr. Fenner! Wanted to update you as to the situation - I checked the water chemistry and the only thing that was off was the nitrates (around 15, ppm I suppose?) which is a tad unusual considering that with the amount of bacteria in the system the tank has never gone above 5-10. So after I noticed labored breathing from the fish I did a 60% change. <Good move> Several hours later I had lost 1/2 of the total fish in the incident, <... sorry to realize> including the original fish that played the role of the canary in the mineshaft apparently. Shrimp seem to be fine, as do a couple of the surviving fish, although the cardinal looks like he is on his last leg. <IF at all possible, DO MOVE the remaining livestock... fish and non-fish to an entirely different setting/system!> I removed the Cuke from the tank and haven't seen anymore of these "little green balls" since. The water chemistry after letting it sit overnight was perfect. Is there a risk leaving the eggs which inevitably fell into some of the live rock, etc? <Not much> Or would it be like any other organic matter and simply raise the ammonia or nitrate? <Perhaps just the dying fishes> I just want to make sure that as they dissolve they will not toxify the water. One last question (I promise!) was what commonly available food do you recommend as an overall feed for inverts in a tank (corals, dusters, apples, etc). <Do general my friend... possibly just a large, healthy refugium tied in... with live organisms being produced, exported from there> I know that is a question which is a bit silly considering that all of the above feed on different particles of different nanometers, but thought I would ask anyhow. The info I have read on the apples indicate their feeding apparatus can only capture particles ~<50 nanometers. Thanks again! Alec Parodi Valencia, CA <Keep studying, applying yourself my young friend... Consider writing your experiences, fields you are interested in... into articles for sale. Bob Fenner>

Re: Indonesian Sea Apple 8/15/07 Thank you very much kind sir, have spent most of this morning on the site (which BTW I was excited to see referenced as a, well, reference in the last issue of Tropical Fish Hobbyist Magazine)! Alec Parodi <Ahh! Thank you Alec. Bob Fenner>

Horseshoe Crab Health and Cucumber Fission 4/5/07 Hello! <Hi Susan!> I just recently found your site and have learned a great deal from it already. <Thank you! How may we help you today?>. I have a 30 gallon tank that I have had for about 4 years. I purchased a horseshoe crab, sadly, since I have read your article, 3 years ago. <Wow, considering their specialized needs, 3 yrs in a 30g tank is a long time for one of these guys to survive!> He has seemed to do well until the past week, he has molted twice during the time I have had him. <Depending on his age, he should have molted more than this over a three year period> He now has a dark brown color to his back, his shell is soft and he does not seem to be moving his gills very often.<Did he just molt in the last day? If so, that would be normal. Their shell doesn't harden for around 24 hrs. If not, that combined with the slow gill action sounds like he's in trouble. How is everything else in the tank? What are your water parameters, including calcium? Have you ever tested for Iodine/Iodide? Is he still eating and if so, what do you feed him? Also, how large is he now?> He also is spending a lot of time upside down.<Horseshoe crabs sometimes do odd things but all in all, I'm concerned for the little guy> I do hope I have not starved him or caused him other harm. <If he survives, he really needs to be in a tank more equipped for his needs. Please read the FAQ listed as "Horseshoe crab Overview 4/14/03" at this link: http://www.wetwebmedia.com/horseshoecrabfaqs.htm > It is a shame that some fish dealers do not have the knowledge to help educate people on purchases. <Agreed. Horseshoe crabs are wonderfully interesting creatures that in the right setting, can be very hardy. Unfortunately, they're not well suited to the warmer, predominantly rock filled reef tanks that most saltwater enthusiasts keep> I will not make another purchase without checking your site first. <Yes, it's a difficult lesson that many of us have learned the hard way, but the good news is that by you writing this, you may be saving another life down the road> I also have a light spotted sea cucumber that recently divided into two sea cucumbers. Both "halves" seem to be doing fine but I have not been able to find any information on this. I would appreciate any help you could give me. <Ha! Thought you were seeing double, didn't you? Actually, "fission", or splitting into two parts in this case, is normal for some species of cucumber. Interestingly enough, these species can reproduce sexually or asexually. What usually happens is the Cuke will disappear for a bit, maybe a week or two, then reappear as two separate entities! How neat is that? Here's a link to our FAQs on Cuke reproduction: http://www.wetwebmedia.com/cukereprofaqs.htm > Thank you for your time and expertise.<You're very welcome, Susan! -Lynn> Sea Cucumber Worries, Nah, Just Fission.   2/23/07 Good day to all, <Hello Robert, Mich with you tonight.> I have what was sold to me as a Holothuria thomasi but I believe is actually a Holothuria hilla.   <OK.> This interesting guy has been in the tank for about 8 months and has grown a good deal with no problems until now.  I lost track of him about 2 weeks ago, last evening I noticed him on the left side of the tank.  My wife mentioned she saw him on the right side.  Hmmm, seems I now have two half cucumbers.  I gave a nudge to each half and they reacted by recoiling.  Not as quickly as I would have expected, but not dead either.  I could not see any trauma, but I have only been able to find reference to sexual reproduction.  Can these guys split?   <Yep!> Would you assume the worst and pull it now?   <Nope!> The only other thing in the tank that might have the pull to render the Cuke in two is a serpent star that was added about a month ago. <Most likely a natural event.> Thanks for your thoughts, excellent resource you have created. <Welcome!  -Mich> Robert D

Cucumber regeneration and Cleveland club Christmas party Gents: <hey... we work for a living <G>> No question this time, but a follow up to a previous question, prompted by  Anthony's recent appearance as the featured speaker at Cleveland Saltwater Enthusiasts Assn. (C-SEA).  Kudos for an excellent program Dr. C. Ha! Thank you... but I'm no doctor... I don't even play one on TV> About 3 months ago I wrote asking about the prognosis for a Turd cucumber (Please insert appropriate scientific name here) <yes... Cucumarid poop-a-loticus> that was caught in a  powerhead.  The cucumber lost his Cuke-  as about the anterior fourth of him/her was ground up.  I removed what was left from the powerhead inlet and put it into a quarantine tank.  The ground up tissue became necrotic and sloughed off. The open wound healed over, and he/she <they> wandered around the tank with no sign of regeneration and differentiation of the anterior structures for about 6-8 weeks, during which time it lost about half of its body mass.  Then there appeared to be some growth of branched structures over about 2 weeks.  Last week I observed what appear to be tentacles that were moving sand grains.  I placed it back in the main tank, and it continues to handle sand grains and move them towards the mouth.  I have yet to see any production of fecal sand pellets, so I am not sure if it is really recovered, but here's hoping..... Thought someone might find this interesting. <an awesome story! Thanks for sharing. And ever more proof that cucumbers don't wipe out aquariums with toxin at whim. Such events are rare> PS.  The Cleveland Saltwater Enthusiasts Assn. will be holding their annual December meeting/Holiday Party and Raffle extravaganza December 20th at 7:00PM in the Cleveland Zoo Aquatics/Cat/Primate Building. This is an excellent opportunity to met others in the hobby, win some great stuff, and support the club's ability to bring in superb speakers such as Mr. Calfo. AND you get a chance for behind the scenes tours of the Zoo Aquarium.   A BARGAIN AT TWICE THE PRICE....Thanks Gents.  Stan <best regards, my friend. Anthony>

Sea Cucumber To whom:  I have an orange and white cucumber I believe it is the species: Holothuria hilla.  I noticed this week it had been split in half, each end looks fine, no damage, or leakage.  Both halves are moving and looking normal. Is this normal? I heard these guys can regenerate their stomachs but what about this??? Please help, is the rest of my tank at risk?? all the levels are good.  Anissa <hmm...this is curious. In general, echinoderms are amazing regenerators. If behaviors look normal, it (they) should be ok. keep a close eye on it for necrosis around the edge of separation.  best, Chris>

Sea apples -Nooooooooooooooooooooo!!!!!!!!!!!!!! - 11/24/03 Hello I believe I have a Australian Sea Apple, and the other day it was secreting yellow little balls, possibly eggs. <Possible...either way....not good!!!>  But the next day 2 of my fish died. <Craaaaaap. Sorry to hear about that. Yes, well, this is why these are not good in mixed aquaria. Either dedicated tanks or not at all my friend.>  I was curious if it was from eating those balls. <Absolutely, but just being in the tank with this noxious material would be enough to kill everything in the tank! Doesn't even take eating it. Do read about this on our site.> I did a 90% water change <More frequent water changes with about 30-50% daily might help. 90% percent was probably necessary though. Do read up before purchasing any inhabitant you are to take into your charge. Good luck ~Paul>

Baby Sea Cucumbers Happy New Year! <To You as well!> I have a couple of 6 inch sea cucumbers (Holothuria spp) in a 20 gallon new fish quarantine tank for a couple of years (and no, I've never had a sea cucumber poison a tank).  Nothing fancy, Bak-Pak skimmer hang-on system and monthly water changes with recycled "used" water from my reef tank (when I do that water change).  About a month ago, my son saw this tiny 1/2 inch sea cucumber on the glass, and we've subsequently found about 20. <You probably don't want this many in your tank. Perhaps you can get someone to take some off of your hands for you as they grow.>  The biggest is now about 1.5 inches.  I've seen some stuff about commercial sea cucumber aquaculture, but haven't been able to find anything about this happening in a hobby aquarium.  Have you heard of this? <Yes. I had 2 Yellow ones that became 4 by splitting. Fascinating to see. Others have been known to reproduce sexually.> BTW, I have no idea why this happened. <The birds and the bees...> The only thing I can think of is that the tank will occasionally heat up into the mid 80's (we live in Miami, and my mother-in-law likes to turn off the AC), and I've seen in the aquaculture literature that raising the temperatures will induce Cukes to spawn. <Perhaps that's it.> Thanks! Kelvin Lee <No worries. Steve Allen>

Yellow Sea Cucumber Fission (11/28/04) Hello, <Hi. Steve Allen, echinoderm enthusiast, answering this evening.> I just got one Colochirus robustus 2 weeks ago and now it looks like it is splitting in to two parts? <Lucky you! Two for the price of one.> It just looks like the other part moves other direction than the other and between those parts there is like intestine or something like that? So what is happening it looks really strange, the cucumber looks otherwise o.k. Thank you in advance. John Hyttinen <It is very common for this species to multiply by fission. I bought 2 and now have 6. They split in the middle and the front part grows a new tail and the back part grows a new front. I suspect that what you are seeing that looks like intestine may be the tentacles of the back parts new front end. If all goes well, the two sea cucumbers will grow and thrive. Is there anything in your tank that might have bitten or cut it in half? This, of course, would be bad, but I'd bet your dealing with reproductive fission. Way cool. Let us know how it turns out.>

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