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FAQs about Sea Cucumber Compatibility

Related Articles: Sea Cucumber, Marine Scavengers, Sand Sifters

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

Chaetodon selene Bleeker 1853, the Yellow-dotted Butterflyfish. Most fishes won't touch Cukes... but some individual triggers, angels, puffers, large wrasses...

wasting midas blenny... Cuke Incident 11/4/11
Greetings WWM crew,
Over the last few days, I've noticed that a midas blenny that I've had for about a year is looking thin and lethargic.
<Mmm, bad behavior>
This morning I found him laying at the bottom of the tank looking rather sad, and while he swam away when I tried to net him it was a rather pitiful attempt. He scurried into the rockwork and did not come out for a morning, garlic-soaked feeding.
The tank he inhabits is a recent upgrade from a 55 to a 90 occurring about 6 weeks ago. The switchover went better than expected with no fish or coral loss. However, 3 weeks in we noticed several missing fish, and the ones that could be found were breathing heavy. <heavily>
After frantic water testing- all of which showed good results
<For what we have tests for...>
- we realized that a black sea cucumber in our refugium somehow got into our pump well and was sucked into the protein skimmer.
The dreaded 'cuke nuke' took out 6 of our 14 fish, but after a 25% water change and the introduction of fresh carbon (and heavy skimming), all the survivors recovered. Well, all except possibly the midas blenny.
<Appears so>
As mentioned, he had been a bit lethargic but was still eating and otherwise acting normally - until today when I found him in his pitiful state. Water conditions are within normal parameters: ph 8.0 (lights still aren't fully on); 0 ammonia and nitrite; very slight nitrate and phosphate (under 10 and .036); 1.026 salinity; temp 79 degrees. A 10% water change is scheduled for tomorrow, and while we used to do so weekly we've been advised to hold off since it's a new-ish tank.
I'm not sure if the blenny's condition is residual from the cucumber disaster or if we should be concerned about something else.
<Likely is the Cuke... fishes, aquatic animals, poikilothermic life often has such "residual" issues; delayed reactions following a challenge>
Other tank inhabitants include: maroon clown, niger trigger, pink spot goby, mandarin goby, scooter blenny, fairy wrasse, red hawk fish, 2 pj cardinals and 2 flame fish, and a small Sailfin tang. We have an active clean-up crew with several starfish along with pink, yellow, and tiger tail Cukes (all thriving), and a copious copepod colony thriving in our refugium.
Any advice would be much appreciated.
Thanks in advance,
<I'd keep offering food (do look into Spectrum pellets, really, as a staple)... and being positive. Cheers, Bob Fenner>

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:

Can I..... Holothuroid poss. poisoning event 2/10/11
Good morning!
I have a tiger tail sea cucumber and he was floating this morning
in the refugium (we had a tank break and live rock and him were put in the refugium). Yesterday we removed the rock because the new tank arrived and it appears that he decided to float. I immediately took him out and put him in a bowl and now he is not floating and he has moved. I know when they die they let out a toxin but I do not know if he is dying or just doing something different than I have ever seen him do before so my question is
1- Is he dying?;
<Is at least toxified>
2-If he is dying did he release any toxin?;
<Do your other livestock register such?>
3-If he is dying (and released toxin) can I use the live sand that was in the refugium?
<Best to do a bioassay>
I would really hate to dispose of established 30-40# of florida live sand.
The water of course would be disposed of.
What should I do?
<Test it w/ other life. Bob Fenner>

Holothuria edulis Behavior, incomp. w/ Zoanthids 11/5/10
Hello WWM crew!
<Hello James, nice name by the way.>
I've noticed some interesting behavior from my sea cucumber I thought I would pass along.
Last night I noticed in his pile of "pooped out"(lack of better term) sand he had ingested a small colony of Zoanthids and given them back to me intact. Today, neither of the involved parties looks affected, but this is a behavior I had never heard of so I figured I would pass this along! Keep an eye on what's laying in the sand with those guys around!
<And thank you for sharing with us. Will post.
James (Salty Dog)>

Edible or Burnt Hot Dog Sea Cucumber Poisoning Event -- 03/04/10
An Edible or Burnt Hot Dog Sea Cucumber was chewed up by a powerhead; I have read these can kill fish.
<<Indeed, the viscera are extremely toxic to most fishes. Time for dilution/water changes and increased chemical filtration (e.g. -- carbon and/or Poly-Filter)>>
Overnight 4 fish are showing signs of labored breathing, Long nose Hawk has passed on, can't find a Flame Angel. I did a 15 gal. water change on a 75 gal. DAS tank,
<<I would do another 25g water change and then watch/be ready to do another if the fishes still show signs of distress>><RMF would move all fishes to another established system. Stat!>
changed out the carbon,
<<Increase usage here, if possible (e.g. -- temporarily add a small canister filter filled with carbon)>>
replaced wooden air stone for protein skimmer. The tank is 13 years old and very stable, with live rock, softies, a couple of LPS, and a Sebae and Bubble Tip Anemone. Any other suggestions?
<<As stated'¦you're doing about all you can here>>
Thank you
<<Quite welcome'¦ EricR>>

Sea apple poisoning 11/22/09
I read what articles I could find about sea apple problems, but my question is different. Some time ago I started losing fish in my 120 gal tank. I checked for predator crabs, poor water parameters, parasites, etc. What I and my mentor settled on is sea apple poisoning.
My fish were dying, but everything else was fine, even my clam. I did a complete water change, rinsed my rocks, and started over doing frequent water changes.
<Mmm, might need to do more...>
Last week I started to restock after trying a couple new fish, bringing my fish number up to 12, adding some new corals and an anemone.
<Anemones are problematic thus placed with other Cnidarians>
my tank looked as good as it ever had for a few days, and then one morning I had 3 dead fish, and several more have died since in a 30 gal. tank. I had stirred a little sand the day before. Did I release more toxin from my sand?
<Maybe... but in all likelihood your previous cleaning was insufficient.
There may well be added complications of allelopathy twixt the new anemone and "corals">
I am going remove all my sand, clean my tank, start over and re-season my tank, but do you think that my rock is non-usable?
<Yes... with some chemical filtrant use...>
Perhaps I can soak my rock
separately and use later?
<Soak it in?>
Replacing 130 lbs of rock is not economically feasible at this time.
Thanks for your advice. Jeff G.
<Boyd's Chemipure, Poly-Bio-Marine's PolyFilter... See WWM re these, and consider moving out the Actinarian. Bob Fenner>

Re sea apple poisoning 11/22/09
Sorry...I neglected to mention that I removed my Cuke and apple earlier with no intentions of reintroducing them. Also, did you mean that with proper chemical filtrant my rock would be usable?
I also meant to add that my tank redo includes all new sand just in case.
I realize my cycle time will be increased, but better safe than sorry?....
<A useful and usually valid statement. You could thoroughly freshwater rinse, air-dry the present sand, use at some later point. Cheers, BobF>

Re: sea apple poisoning -- 11/22/09
Is it necessary to replace all my water, or just extensive cycling with good carbon and poly filter....and if so, how long should I cycle at 1200 gph before adding fish?
Thanks very much for the help!
<... I would run the system a week with the filtrants, try a few "test damsels" after for a week. RMF>

Re: Sea Cucumber Concerns 9/29/2009
Sorry about that! Here's the photo from Saturday from before he ejected it.
Try this...
<Nice pic>
Unfortunately the 50-gallon tank is my only saltwater at this time, but I am going to move fourth with plans now to convert a 20 so the damsels will be getting evicted Very soon. I needed to get those pests out anyway, even if they are cute.
I just hope they were his main source of issue.
Are these guys really that finicky to keep?
<... Please read here: http://wetwebmedia.com/seacukes.htm>
Thanks again for your helpful and non-judgmental help you always offer. I know I should have done more research before buying him (I'm no new fishkeeper), and some are quick to point out this flaw... which
of course helps me avail the situation none! There is always much to learn.
<Indeed... More for me every day. BobF>

Sea Cucumber -- Remove Or Best To Leave Alone? -- 7/19/09
Hello Crew-
<Hello Andrew, Lynn here today.>
First off, like most that write you I would like to express my thanks for a great, informative site. The FREE information you provide has been priceless to me as well as many others, I am sure.
<On behalf of Bob and the crew, past and present, thank you very much!>
I used Google to find an answer for my question but had no luck. I did find some pictures of Sea Cucumbers that appear to be similar to the three that hitch-hiked in on my Gulf of Mexico live rock. However, I didn't find much info on removal without killing and/or stressing them to a point that they nuke my tank. The problem is that these guys live in very tiny crevices in my rock.
<They sure do. I've received many shipments of rock from Florida/Gulf of Mexico and these little guys have been in every single one.>
They never venture out of this area - they are totally stationary. As far as I can see, any attempt at removal would inevitably destroy the organism.
<Likely so, yes.>
So, my questions... Do you know of a method of removal for this type of organism?
<Not that wouldn't do harm. If your little Cukes are anything like the ones I've always received (they do seem to be), they're covered with tube feet that keep the Cuke anchored in place within the rock. This would make suctioning them out with something like a turkey-baster, or small siphon, next to impossible.>
Can you tell from the picture I am including if this is a "very poisonous" or "only a little poisonous" Cucumber?
<No I'm sorry, I can't, but I can tell you that I've never personally had any problems with the small Cukes I've received over the years (in 20g and 30g mixed reef tanks). I've always run carbon just in case though, and kept up with regular/maintenance water changes. Sadly, as neat as the little Cukes were, they never lasted more than about 6 months.>
I can't tell how big the entire animal is, but with its tentacles extended, they are about the size of a quarter.
<That's typical of the ones I've gotten over the years as well. Some were smaller, but I've never seen any larger than about quarter-size. As far as body length, those I've received have never been longer than ~1.25'.>
As I said before, I have discovered three of them and they are housed in a 30 gallon aquarium. They are very pretty and fun to watch as they suck food off of one tentacle at a time.
<It really is neat, isn't it? They use those sticky branched tentacles to trap/catch whatever particles or critters that drift by, including detritus, microalgae, planktonic larvae, pods, and other organic material. Once something's caught, the tentacle curls in on itself, taking the food into the mouth, then unfurls back into place.>
So far they seem to be doing well, they stay open and feeding most of the time. I have been target feeding Phytoplankton about three times a week... The tank as a whole is very healthy with all its numbers spot on. It has been up and running since Jan '09.
I would like to leave them be (unless you think this is unwise)
<I'd leave and enjoy them. These guys are usually so small that when they do die, they don't seem to pose too much risk in a tank such as yours, or larger. Now, if you had a big sea apple in there, I'd be singing a different tune!>
..however, I feel like it would be a good idea to have a plan in place to get them out if things start going south. Ideally without removing the rock that they are attached to from the aquarium.
<If you're at all concerned, I'd recommend running carbon and having some ready-made saltwater on hand for a quick water change. You could also try suctioning the Cuke out of its crevice if you think it's dead or dying. At that point, the little tube feet may have already loosened their hold on the rock, or be barely hanging on. For a bit more information and a photo of some of the Cukes I've had, please see this link: http://bb.wetwebmedia.com/gallery/viewpic.php?pic_id=61
See the FAQ titled 'Anemone-Like Creature ID: Rock-Dwelling Cucumber -- 10/21/08', for a similar Cuke, at this link: http://www.wetwebmedia.com/cukeidf3.htm
More info here: http://www.wetwebmedia.com/seacukes.htm >
Again, thanks for any insight you can give me on this subject and sorry if this topic is already covered. I really did look but found nothing.
<No worries, we're here to help!>
<Take care, LynnZ>

Question on Cukes/Compatibility 5/19/09
<Hello Richard>
I recently purchased a Cuke..a Pentaca anceps..has a greenish body with pink knobbys on the outside of it.. attached is a picture...
<No attachment found.>
Now I have had several different opinions on this creature..being a sort a sea apple ..and has been said to get it out of my display...I have a 275G mixed reef w/a 75G sump/refugium....I know they are toxic...but is in great health and has no holes or anything on its body..So..I was told that they are reef safe and when it dies..it will just be eaten up by the clean up crew...And I have been told get it out when it dies..it WILL release its toxins and wipe out my whole tank..coral, fish and all...SO My question is...What do I believe...Can I keep it in my main display and when it dies it will just be eaten OR is it a high risk..and when it dies will release all of its toxins and wipe out my tank???..I doubt I have anything that will pick on it to make it defend itself..and release toxins...
<Sea Cucumbers emit a toxin called Holothurin. If you notice an oily residue on the surface of the tank, cloudiness and/or discolored water, there is a very good chance that toxins were released. If bothered by hermits, fish or any other animal it shares it's tank with, it may eject it's viscera as a survival mechanism and kill off some of the fish and/or invertebrates in your tank also. So, there is some risk in keeping a Cuke. Do read here and related articles/FAQ's
Thank you,
<You're welcome. James (Salty Dog)>

Re Question on Cukes/Compatibility 5/20/09
I read there..but you didn't really answer my question...
<Sorry about that, I see I missed a "paste" during editing.>
When it dies..does it omit <emit> the toxins or does it just die and the clean up crew would eat it up with no worries..
<It may or may not emit toxins, and when it does die, I would remove to be on the safe side.
James (Salty Dog)>

Re: Question on Cukes/Compatibility 5/21/09
Thank you..
<You're welcome.>
but too many variables and don't think I will take the risk in my display....
<Is why I've never had one in my system. James (Salty Dog)>

Sea Cucumber Hitchhikers, incomp. in this case 2/19/09 Hello Crew, <Hello Joseph> I have a "sticky" problem caused by about 10 small Sea Cucumbers that were hitchhiking on Florida aquacultured LR I purchased. At the time I did not know what it was, but now after seeing Bob Fenner's article Gad-Zooks Cukes, several of the Cukes expelled their Cuvierian tubules while the LR was in a large plastic container. The picture in B. Fenner's article on the eversion of these tubules is exactly what I saw. I placed the LR in my aquarium and noticed dead small crabs, cucumbers, bristleworms and even a dead mantis shrimp on the bottom of the plastic container. A few of the approximately 1.5" Cukes were still alive and were placed in my tank (God help me). I, now, have noticed some long threads flowing from the powerheads that look just like spider silk that I believe are the sticky Cuvierian tubules. I see no life in my tank, even when using a flashlight to try and catch bristleworms or other nighttime foragers, nothing but a few button polyps and what looks like a glass anemone (wouldn't you know it?). <Yep, seems like nothing kills them.> Question: Can I skim and use charcoal to remove any possible toxins or do I have to start over? <Obviously you have removed the Cukes, and if not, do remove them. Protein skimming and use of Chemi Pure should restore water quality in a few days depending on your filter's flow rate and efficiency of your skimmer. Personally, I do not like Cukes, too risky.> Nuke the Cukes! Thank you, <You're welcome. James (Salty Dog)> Joseph Rouse

Cucumber ID/Compatibility 12/18/08 Hi Crew, <Hello Carlos> It's been a while, my system is now 2.5 years old and absolutely cruising. Thanks for all your help these past two years. <You're welcome.> Well I wanted to add some new live rock to the system and replace some of the sand. What should I find in the live rock, but this little guy. At first I panicked thinking it was going to it's "puking thing" and wipe out my treasures.....but it let me take it out without harming anything. I have it in this isolation holder at the moment and will probably move it to my hospital tank for now. I have searched all the pictures and can't quite place the species. Any Ideas? Is this one the in-patients types or one that will be safe? Do you think it will be safe in my main system or should I take it to my local FS? He sure is cool looking, but I would rather not risk it if he is one of the bad types. <What you have appears to be a Holothuria species and are excellent detritus eaters. They are reasonably safe but if provoked often enough, they can release a toxin that can be harmful to fish. This could also happen when it dies. Do read here and related articles/FAQ's before making your decision to display in your reef tank. http://www.wetwebmedia.com/seacukes.htm> Thanks again. You're welcome. James (Salty Dog)> Cheers

Tiger Tail Cucumber, comp. 09/27/2008 Crew, <<Zach>> ?I have been reading on your site, and it seems that the conclusion is that a Tiger Tail cucumber is capable of wiping out a system if it eviscerates, but the chances of this happening in a stable system is slim. I have a 75 gallon reef with 10 scarlet reef hermits, and after reading Marine Invertebrates by Ronald Shimek he states that hermit crabs can bother cucumbers. Is this true. It seems that my scarlets are very peaceful, and go about there business picking at algae and even climb over each other without fighting or bothering anyone. They have plenty of shells to upgrade into as well. <<Yes, I would agree with Ron, this is certainly very possible. Up to yourself is you feel its a viable risk to take>> Zach <<Hope this helps. A Nixon>>

Re: Tigertail Cucumber -11/02/08 Nixon, <Hi Zach, I'm so sorry Nixon seems to have neglected this question.> if I were to bring my ten scarlet hermits back to my lfs in exchange for five or so Mithrax crabs would this be a good choice. I also plan on keeping bubble coral and have read that scarlets can pose a problem in this environment. I'm most concerned about the cucumber. <All crabs present some risk to corals and other vulnerable inverts. The emerald crabs are typically more docile, but there's no guarantee. The best thing to do, if you want to keep crabs of these sort, is to feed them well so that they don't go bothering your other animals.> Zach
<Best, Sara M.>

New Accidental Familial Addition 8/8/08 Hi, <PS> My partner and I just ordered some macro algae for our aquarium and when we got it we found the little guy in the attached picture (sorry for the crappy quality) roaming through it. We think he's an impatiens sea cucumber (Holothuria impatiens) but we're not sure which is why we're writing; <Might be...> we don't want to doom him/her to a life of hardship by turning him over to our LFS but at the same time we also don't want him taking down our whole aquarium as Sea Cucumbers are known to do. <Mmm, not this one> Well some of them are known to do. Some of them, we've read, can be quite beneficial and are nonpoisonous. If we got the species right, we read that this little guy can be either poisonous or not poisonous. <Generally not this one> Yeah we had the same thought: which is and how do we tell? That's where your knowledge; expertise and serious kindness come in. <Mmm, how do you tell... from gross dissection of specimens, accumulated anecdotal accounts... seeing a bunch in friends aquaculture facilities out here in Hawaii...> Any ideas on what the species is if it isn't an impatiens? <Not from this pic, no> If we did get it right, is there a way we can tell if he's poisonous? When we got the algae we noticed that right near him there was a huge glob of yellow sticky mucous looking stuff (it looked like some of it was still slightly coming out). We put two and two together from our reading and determined that this mucky looking stuff was probably the tubules that the species is known to expel (this particular species, assuming we got it right, doesn't eviscerate like regular sea apples and some other species of cucumbers). We read that the tubules from the impatiens can contain Holothurin (but not always) so we cleaned that out before we put the macro algae in the aquarium because we didn't want to lose any of our fish. <Mmm... I would not be overly concerned... if this system is large, well-established, well filtered... should be little actual potential poisoning from this animal> Right now he's in our little refugium which is isolated from the hermit crabs and fish that might pick on him and cause him to hit critical mass and nuke our tank. If we can keep him to give him a good life, we'd like to but again we don't want him killing everything else (or even just our fish) in the aquarium. If you think keepage is a possibility, we'll research on food stuffs that he likes to eat and set him up with a little sandy refuge permanently as our other inhabitants might not be so keen on leaving him be (we've a couple of starfish, some hermit crabs that are of particular worry and our two clown fish tend to be masters of the tank and push the other inhabitants around a little bit). Any thoughts would be greatly appreciated. D <Were it me, mine, I'd keep, enjoy this animal. Cheers! Bob Fenner>

Re: New Accidental Familial Addition 8/9/08 Hi Bob; <D> Thank you so much for your reply. I apologize for the quality of the photograph; it was hard getting the contrast right because h/s is dark and was sitting against a dark backdrop of macro algae. I'll try to describe h/h in a little more detail (for the readers h/s = he/she and h/h = him/her): h/s is a dark molasses colour with largish white spots that run along the length of his body. He speckled with tiny white dots. When we first spotted h/h the spots were flat and he was drawn up to about an inch in length. Once h/s was in the water, turned out the spots were spiny protrusions (the speckles I think were tube feet). He tapers at one end (I'm assuming this is the anal end because it was the end that the ejection was protruding from) and at the other end are his gill/feeding apparatus which he opens and closes as described in much of our reading by extending finger like protrusions and then curling them back in towards him 'mouth'. Hopefully that will give you a better picture. Again, we searched through hundreds of pictures of cucumbers on the internet and the H. Impatiens is the closest species we could find that looked like him. Hope this helps. <A good description... and this species is a frequent hitchhiker on algae culture purchases> Our aquarium is a two year old 45 gallon bow front with about 40 pounds of live rock and about a three inch sand bed. We've got two giant pieces of dead coral that make up little hidey holes for our various residents. We've a Fluval 405 filter <Do make sure the intake screen is in place... and that rock is piled about this to prevent this, other benthic invertebrates of size being sucked up against> with two containers of ceramic pre-filter; two containers of activated carbon, one container of contaminate removal resin (bagged), two containers of poly fine filter media, and two containers of porous bacteria filter media. We have an Aqua-C remora protein skimmer <The intake to this too> and an in-line heater. Our main power head is a magnetic driven type power head that has the drive apparatus on the outside of the tank with nothing but impeller on the inside attached magnetically. <Ditto> The impeller intake is grated and runs the entire length of the of the housing but it is not a fine grating and the output is open, but it moves water all around the entire tank so it's pretty powerful. We test PH and salinity twice daily with the former sitting 8.2-8.3 and the salinity at 1.026. Temp stays at a balmy 78 degrees, <All good> although here in San Francisco we do have a few hot days where it gets harder to maintain the consistent temperature and it has at times risen to 80 to 82. <No worries> Those days are rare and we try to keep an eye on the weather and if it does feel like it's getting warm we use a fan to evaporatively cool the water. This usually works well and the temp usually only fluctuates a degree or so. We do ten percent water changes twice per week (we make our own salt and fresh water from deionized tap water using an adjuster to set the PH for the fresh water and aeration balancing for the saltwater). <Very good> The Fluval is cleaned and thoroughly washed once per week (the bio media is washed in fresh saltwater). We test all of our parameters once a month and at the last testing about a week ago Ammonia, nitrites and copper were at zero, phosphates were at 5 ppm (we've isolated the cause of this and have taken corrective actions), nitrates were at 20 PPM, calcium was at 340 ppm and the GH is 7 degrees. Our inhabitants include two maroon clown fish, about eight hermit crabs, three zebra turbo snails, a cowry, a hatpin and pencil urchin, a chocolate chip starfish, a strawberry and Mithrax crab, two cleaner shrimp, a blood shrimp and two fighting conchs. All are happy healthy and living it up at Chez Aquarium. <Heeee!> So do you think we'll be able to keep him? Many thanks for your help and advice. D <I do think... you are! Cheers, BobF>

Possible sea cucumber problem 6/18/08 Hello, <Hello, Jack!> I've searched and searched, and cannot find any specific answers, so out of desperation I'm asking my very first question! <Sounds good. Thanks for searching!> In one of my labs, I've got a 4 month old, 75gal marine tank (w ~20gal sump) which...until this morning...held only a cleaning crew (snails, hermits, and two peppermint shrimp), live sand, live rock and gobs of green algae. I just received two "Marine Invertebrate" sets and some jellyfish from Ward's Scientific, <mm...yes> and within an hour of introducing the various species (I know, too many at a time, but it's the only tank we've got...I still need to get a quarantine tank going) BOTH peppermint shrimp were in the open, on their sides, twitching. They died about 2 hours later. http://wardsci.com/product.asp_Q_pn_E_IG0013628_A_name_E_Invertebrate+Living+Specimen+Set+1 http://wardsci.com/product.asp_Q_pn_E_IG0013629_A_name_E_Invertebrate+Living+Specimen+Set+2 http://wardsci.com/product.asp_Q_pn_E_IG0013404_A_name_E_Jellyfish+Living+Specimen I took great care to minimize introducing very much foreign water to the tank. <Okay. How did you acclimate them? Did you slowly transition the water in the bags to system water, or did you just release these organisms into the tank? Simply dropping them in would most likely kill them promptly.> Especially, from the sea cucumber bag! I called Ward's, and they could only tell me that the genus/species was "Cucumaria". <Generic...> Nevertheless, I suspect the Cuke got freaked out in transit and spewed some toxins upon arrival. <Much more a predation response than environmental> Are there any other possible explanations, given the long list of newly introduced critters (check the ward's links, above)? <Be advised that the animals sold by Ward are not compatible with each other, and are rarely properly identified by the company. In my experience with these sets the instructions for care are poor, and the animals sick or doomed upon arrival. The jellyfish, for example, are completely unsuitable tankmates for the other offered specimens, and will require special aquaria to house them. Most of the echinoderms sold by Ward simply cannot be kept without intensive feeding and water change regimens- not what a zoology or invert. phys. class needs!> I've done a partial water change. What other precautions should I take? <I would test your water parameters and see if something is seriously out of whack, and review acclimation procedures. Perhaps consider paying a bit more for some select, research specimens from another source.> I promise, to never introduce so many animals to the tank, ever again. Thank you! <No problem.> -Jack <Benjamin>

Re: Possible sea cucumber problem - 6/18/08 Thanks for the prompt response. I've had a few hours to further research the situation, here's an update: 1. Acclimation occurred over the entire morning yesterday: a) each bag was floated for 1 hour; followed by b) adding tank water to the bag (1 pt tank : 2 pts bag volume) and another hour of floating; followed by c) emptying 1/2 of that water (into sink), topping off w tank water, and floating for another 1/2 hour; and finally d) adding critter to tank while minimizing the introduction of baggy water. Snails and hermit crab were rinsed under tapwater too. <If anything, this might have been too long, but since you had them floating temperature shouldn't have been a problem. I doubt acclimation was the problem.> 2. Nobody else was dead this morning. Yay! <Glad to hear it!> 3. I no longer attribute the shrimps' demise to the cucumber. A more likely suspect would be the jelly's. They'd shed lots of slime (nematocysts?) in transit, and 2 out of 3 had actually LOST THEIR MANUBRIA...incidentally, the injured jelly's and detached mouth-pieces are still pulsating on the tank's floor. I now hypothesize that the shrimp were knocked off by free-floating nematocysts. <Very possible! Cnidarians can shed a lot of stinging cells under stress.> 4. I consider the Cassiopeia's doomed if they remain in this tank, and a hazard to whatever strolls past them. <Both correct.> I'm setting up a temporary 10gal w/ steep live sand "banks" on either end, and setting up a weak submersible filter on the bottom to create a pseudo-circular, vertical current. I've got some high-power full-spectrum fluorescents (used on lizards) I can put on a timer, too. Meanwhile, I'll see if anyone around here wants em (LFS, Bio dept, aquarium...) and, worse case scenario, I'll preserve them for our teaching collection (I waste NOTHING around here!). <Sounds like a good plan.> 5. More research has me concerned about the Featherdusters and predation from: red and blue-legged hermits, brittle star, and the urchin. Real, or paranoia? Time will tell... <There is certainly risk, but they should be fine. Hermit crabs will eat just about anything, given the chance, but as long as there is easier food to be found, they probably won't be going after something the have to catch.> The determining factors in choosing Ward's over the LFS: very good prices (surprising, actually), guaranteed delivery, a 20% off coupon and an established tax-exempt account. <Understood.> The lack of documentation was acceptable, since I'm quite capable of researching various problems, <Clearly. You definitely did your homework before you wrote this reply!> but I'm ashamed to have assumed that their sets were compatible...and to have created this Darwinian situation. <Selective pressure notwithstanding, compatibility and mortality are perpetual problems in aquaria. I wouldn't lose too much sleep over your assumption- it is reasonable to expect that sets of specimens from a reputable supply company would be compatible...that said, often time accuracy is sacrificed to Mammon in this hobby.> I should have known better, given that they included Aiptasia anemones in one set! <Probably helps keep the price down...and, given they aren't overfed they can be fascinating. You might be interested in information re Aiptasia culturing/filtering...use of Aiptasia to clean water.> Best regards, -Jack <The same! Benjamin>

Black Sea Cucumber 6/16/08 Hi Crew!! <Hello!> Let me first start out with a little background on my tank. Currently running is a 50gallon breeder with a 20gallon sump (tank set up for about 6-7mo, but sand has been alive for about a year, since I used it for my upgrade). I have a modded 6-2+ euro-reef skimmer, with ATO sensors and carbon/phosphate media being run 24/7. I'm working on adding a DSB to my refugium section of my sump with some macro. All fish are friendly and peaceful, also have a serpent star (would he bother a sea cucumber?) Water conditions are as follows: temp 79-81 pH N/A my local fish store is temporarily "living in the streets" so to speak with their pH probes <Decent electronic pH probes made by Hanna can be purchased online from places like Drs. Foster and Smith or Marine Depot for a relatively low cost.> , Ammonia 0 Nitrite 0 Nitrate 5 dKH 9 Calcium 425 Magnesium 1050 (however have added some Mag to get it up around 1200) Salinity 1.025-1.024 and Phosphates .1 And now for the actual question! :) A buddy of mine just tore down his 75 gallon tank and set up a 26gal Nano...he had in the tank two sea cucumbers. Now that his tank is much smaller he is selling his black sea cucumber which is about 6". I would like to know how this animal would fare in my tank, I have a lot of flow in my tank (Mag 24 closed loop) however there are parts of the sand-bed that don't quite get enough flow, and I do not want to add more power-heads! I'm kind of scared to add a sea cucumber for fear of it dying/leeching its guts into the water, however I also feel my system my benefit from adding one since there are areas of detritus/buildup on the sand-bed that he could eat! probably the reason why my nitrates are at 5) so I am here seeking the advice of the experts. the cucumber is very healthy I have seen him periodically when I'm over at my friends and he's always eating sand, and I'm worried that he doesn't have enough to eat in the 26 gallon he's being housed in now (another reason why I want to add him to my 50 gallon) I would add him in a heart-beat if he was not poisonous and had the potential to kill off everything in my system, so I'm very much on the fence as you guys/girls can tell (and trying to do my homework before I just add something to my tank). I just want to make sure if I do end up adding this guy to my set up that he would aid in my efforts for a better reef, not cause more headaches and problems! Sorry for the long post but I wanted to add details, I have see other posts that don't include details and its hard to learn from them or even answer them I'm sure! <I would think you're good to go on the cucumber; the key is to avoid sudden stress. Careful acclimation and handling should keep him from dumping his saponid tubes. Cucumbers that die of gradual starvation are very unlikely to poison a tank- secondary compounds are energy-expensive to produce, and a starving animal will stop reproductive and secondary metabolic pathways first. Provided you have fine sand, this animal should do well in your tank.> Thanks again!! This site has helped me save lots of animals/inverts/corals in my year of reefing! <Glad to hear it. Keep reading, enjoying, spreading the word.> Keep up the phenomenal work! <We'll do our best. Benjamin>

Potential problem with Tigertail Cuke, and Dendrophylliid hlth. 2/10/08 Hi crew- <Jim> I have a very healthy 75g reef tank with a 20g sump and 10g refugium. This morning, I noticed something odd - my 6-ish inch long Tigertail Cuke was scaling the wall of my aquarium - never seen THAT happen before! He has been in this system for a few years, and reproduced (by splitting) once a while ago (I pulled out his buddy). My wife noticed a white gash or laceration running down his body, at least several inches long. We did the smart thing and pulled him immediately from the tank. Suggestions? <Mmm, isolate... oh, I see below...> I don't have an isolated system to put him in so that he can heal up. Am I better off without him in a system this size at any rate? <Well...> Should I euthanize him or take him to a LFS? <The last> I presume that the one thing I should NOT do is to put him back into my system. <Not necessarily... life IS risk... some minor sub-risks are to be weighed, chosen...> All other inhabitants of the system are FINE. Here is what the system looks like: http://picasaweb.google.com/javagiant/Reef12808 <Wow, quite a mix... Soft and hard corals, other cnidarians, including an anemone... an apparently healthy powder blue tang...> While I am writing, I do have a recent addition (the Turbinaria) <I see this... on the right> that I could swear is shrinking a little. Color is great and polyps are well extended. I did some research, and have begun spot feeding. Will that do it, or does he need more light? <May need to be moved further from the Actinarian... see WWM re compatibility... Otherwise, just patience> I have 2 x 175mh and 2 4' actinic VHO tubes running on this system. Should I move him up, so he gets more light? <I would not> I have been keeping him debris free - anything else I should be doing? many thanks- Jim Gray <From the sparkling looks of your system, obvious health of your livestock... Running a public aquarium or helping at an LFS. Thank you for sharing. Bob Fenner>

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>

Sea Apple = A-Bomb 03/25/07 I am completely heartbroken and devastated. All the fish in my main saltwater tank (135 gallons) were just killed by a Sea Apple that eviscerated while I was at work except for three fish. <Unfortunate, but all too common. I am sorry for you loss.> Only two paired Ocellaris Clowns and one Blue Green Chromis survived. Fifteen others sadly died, including four cleaner shrimp. Apparently this happened when my local electric company temporarily terminated electricity and my equipment turned off. I came home to find the devastation, dead fish everywhere and the worm-like insides of the Sea Apple were all over the tank. <Such is the risk of keeping Holothuroids in a populated tank. Evisceration is really more of an eventuality than a risk. It most likely WILL happen and at an inopportune moment.> By the way, there were all kinds of unidentified creatures in the tank that I have never seen before, some were crab-like, others had shapeless forms and were about a half inch wide, what are these things? <Various Polychaete worms, and other crustaceans most likely. Impossible to say for certain without a photo, even then exact I.D. is hit or miss.> Fortunately I had a second tank where I put the three fish (24 gallon Nano). They seem to be doing OK. <This is a good thing. Why don't you have a Quarantine tank?> Unfortunately, I have a pair of established Tomato Clowns that immediately started hassling the Ocellaris' and the Chromis so I caught one of the Tomato Clowns and put him in a ventilated breeding unit to isolate him from the others. I am working on catching the other which is hiding in his Bubble Tipped Anemone, I hate to have to do this but I want the stressed fish from the other tank to be able to relax and de-stress without being chased all over the tank. <Another reason to have the quarantine tank.> Do you think this is a good idea? <Would be better to have a quarantine tank. Go purchase a 10 gallon tank, and a heater and filter. Place some established media from the Nano that you have into it's filter. Then place your stressed fish into it. This is much better than hassling an established environment.> I need advice on what to do now with the main tank. <Siphon out the remaining viscera, and about 70 % of the water. Over the next few days do a 20% water change each day. This should dilute the poison. Make sure that you get ALL of the dead animals. They will be broken down as part of Nitrification, and will pollute your tank.> I will remove the dead fish but what do I do with the corals, they seem to all be fine, will they survive? <Hard to say. Time will tell.> Should I remove the corals immediately to plastic container with chemically adjusted RO water? Or should I risk putting the corals in my 24 gallon Nano? <I would follow the water change plan firstly. Then if the corals start to degrade I would consider moving them. You don't want to do anything drastic that might crash the Nano too.> Would that possibly poison the water in the Nano? <I would think that the increased bioload would cause problems.> I also have two Crocea Clams, will they likely survive? <Again time will tell. Please see above Re: Water Changes.> After I remove the corals and snails or anything else that is still alive what should I do with the water? I would assume I should completely drain it, is that correct? <Please see above. I would NOT drain all of the water.> What about the live rock and live sand, what should I do with them? How will the worms die and how should I get rid of them? <Not really sure what you are asking. I was under the impression that these worms were already dead. If not, then NO LEAVE THEM ALONE. They are GOOD for your system, and are present in all healthy systems.> Are these worms toxic themselves and if they remain alive in the rock after the cleanup are they harmful to the tank? <No. They are your friends. Likely came out because they sensed carrion which is what they eat.> After a complete water change which I'll assume I should do, how soon can I replace any fish and corals? <Do not do a complete water change. I would do one large change and then a few days worth of 20% changes, and then a weeks worth of small 5-10% changes. Start adding fish one at a time and QUARANTINE them. I would say one fish every two weeks.> Should I treat the tank in any way? Do I have to completely recycle the tank? Could you please take me through the proper steps I should take at this time, I need help. <If you don't change all of the water at once you should be fine. There are obviously some creatures that survived.> When I eventually pick myself up and slowly add fish back to the tank I vow to always listen to the advice of the WetWebMedia crew. You guys know what you are talking about. <Thank you for your kind words.> My story is probably a typical one; I asked about Sea Apples from a LFS and was told that they were harmless filter feeders. <More or less true, unless you irritate one.> I was attracted to their bright colors and figured I could trust the store owner. I didn't do my research and found out a few days later through your site that Sea Apples were potential killers and should be avoided. <Doh! You should always research before purchase.> I contemplated returning the Sea Apple and was strongly leaning toward doing just that until I did some further research with obviously less well-informed "experts" that theorized that a tank wipeout was extremely unlikely. <They obviously have not kept Holothuroids for extended periods of time…> They also said that most of the fish would survive even if it did happen and there likely would be time to get the fish out. <Again Holothurin/Holotoxin is a very powerful neurotoxin. It also depends on the kind of Holothuroid that you have. Some are worse than others.> Unfortunately, you were right and they were dead wrong and my fish paid the price. <Sad to hear this really.> I feel responsible because I was forewarned by you after I bought the Sea Apple. I had a healthy thriving tank with no deaths for seven months. The water was good, I was doing routine water changes, all the fish were healthy and I had the Sea Apple for about six months with no problems. I have learned a painful lesson and I vow to be a more conscientious fish owner from this point forward. <We all learn from our mistakes. Everyone was new to this at some point.> I usually follow your advice to the tee but all I takes is one major mistake. I also learned to never trust my LFS without doing research before hand. I know this is a touchy subject but what would you do in this situation regarding the LFS that sold me the Sea Apple. What action and I don't necessarily mean legal action would you take. <I would make my situation know to them. If they seem unconcerned or callous about your plight, I would further go to the local Marine Aquarium Society. I would tell them what happened and ask that they not patron this establishment. You could put up a blog to share this experience, etc.> I am curious to read your response. In the meantime I can really use some immediate help with this mess ASAP. <I hope that this helps.> Thank You, <You are welcome.> (please feel free to post this for others to read in the Marine Aquarium articles) <This correspondence, like all correspondence to WWM will be posted. Brandon.> Have you received this, I haven't seen a response. 3/26/07 <Yes this was received. Should be an E-mail in your in box waiting on you. I have a copy of the response that I sent. Let me know if I need to resend it.> Where will I see a response, I could use some help with my problem. <You have received an E-mail, and you can check the response on the daily FAQ section of the site as well.> Thanks <You are welcome. Brandon.> Strange wipeout, reef... toxicity... Cuke 2/20/07 I am a reef keeper for over 10 years with several large reefs. I recently set up a 34 gallon small reef. Reef had 4 medium seahorses, 1 percula clownfish, 2 cleaner shrimp, and a medium sized sea apple. Live rock, live sand, and protein skimmer. Everything fine for 2 months or so. Last night everything looked fine. Looked this morning the fish were all dead. The other reefs were fine. The 2 cleaner shrimp were still fine and the sea apple <...!> looked fine with no evidence of a discharge from the sea apple. Last night I had fed the fish in all my tanks frozen Mysis and also put 2 small capfuls of DT's phytoplankton in the water of the 34 gallon reef. 1- Since the sea apple looks fine and no evidence of a discharge or discoloration in the water. I am skeptical he had anything to do with the wipe out? <I am NOT> Can a sea apple blowup or discharge poison and look fine a few hours later and the water look normal? <Oh yes... think about this... Would an organism have some sort of defensive mechanism that would damage itself? Not likely> 2- Could the Mysis have been bad and killed the seahorses and clownfish and not affected the fish in the other tank who were fed the same Mysis? <Mmm, not likely at all> 3- Could it have been the DT's phytoplankton had gone bad? <Nah> I have no idea what happened. <Is only a guess... but am very sure the Holothuroid could have been the root cause here... Have seen this species take out an entire store... on centralized filtration. Other general probabilities include a "bug" (insect) flying in, poisoning the system, an errant use of a household cleaner/aerosol, a cascade-event with some sort of microbial/algal die-off... Bob Fenner>

Cukes (comp.) and ORP 9/6/06 Bob, <Scott> The ORP in my 1300g tank is now hitting 500 at its peak in the night. <Mmm... too high...> All fish, corals and other inverts seem unaffected, if not ridiculously healthy. Should I be concerned or tanking any sort of action to lower it? I'm not running ozone. <... odd... I'd "check your checker" here first... Likely this is off> Also I was wondering if in your opinion (or experience) an Australian Sea Apple would be capable of catastrophically polluting that volume of water if it died. Thanks! <Oh yes... Have seen these take out entire stores (thousands of gallons) on collectively plumbed holding systems. Bob Fenner> Scott

Sea cucumber disaster 8/8/06 I don't really have a question for you, just a cautionary tale you might share with your other readers. <Please do> I went to the LFS this past Saturday afternoon to get an easy-to-care-for fish of some kind, saw a pink and green sea cucumber, and made an impulsive last minute change to my plan. Big mistake. HUGE mistake. I later paid your site a visit for a refresher on Cukes. I had forgotten all about them expelling their guts into the water and pondered whether or not I wanted to take it back and see about an exchange It made that decision for me early this morning when it went nuclear and killed all my fish, though the other inverts seem ok. I did a 30% water change this morning and will do a couple more in the next day or so. I'm hitting it with some new charcoal as well. This is a small tank, so it was only three fish. No real financial loss, but it is definitely irritating and embarrassing. I know 99% of the blame falls on me, but I really wish LFS had said something about a critter that dangerous. The money they made on the Cuke is much less than the money they lost by losing me as a customer. <...> As strongly worded as your warning against Cukes is, maybe you should put some skulls and crossbones and biological hazard symbols on it as well. Thanks for maintaining such a great site. It really comes in handy, especially if used prior to a purchase. Thanks, Ty <Thank you for this. Bob Fenner> Pink Cucumber/System Poisoning - 07/20/06 Dear Bob, <<EricR here this morning...>> I have a pink cucumber who has been doing relatively well for approximately a year in my tank. It's not very active but about a week ago it moved near the overflow box and has become extremely "squishy" and looks very wrinkled. <<Possibly just doing a "water change">> It still sticks out its Feather like tentacles partially from one end and the other end has a hole that appears to open and close like it is breathing. <<All good signs>> My question is, is this squishy body a bad sign. <<Hard to say. In my experience these Holothuroids tend to just "shrink away" once they are on the decline (usually from starvation)...unless something has injured/poisoned it>> It used to be quite solid but now if you touch it you can almost push both sides together (Not that I've tried). If it is a bad sign what can you do to try and resuscitate the poor guy. <<Excellent water quality and adequate feeding>> It's a great addition to my tank and many people love it as do I. <<I too am a fan of these...>> I appreciate any help and if you need any other information let me know. 1.022 salinity <<Would like to see this increased to 1.025/1.026>> 0 ammonia very low nitrates <<Mmm...less than 5ppm I hope>> 0 nitrites ph 8.4 55 gallon with 12 gallon refugium (with mud, mangroves and a little Caulerpa algae with a max 700 gph pump, UV sterilizer, protein skimmer and a power compact. I had a slime algae problem but used SlimeBgone and it was gone in 48 hrs. <<Ughh...a bad practice my friend. Likely the antibiotic has adversely affected the cucumber...not to mention killing off bacteria/other micro-biota the cucumber used for food. And, it is very likely the BGA will only return as you have not addressed the cause with the antibiotic and rarely is the organism every totally wiped out>> Corals and everything else seem to be doing fine. <<We can hope...>> I add snow and phytoplankton about twice a week and generalize its region. Best regards, Jason <<Cheers, EricR>> P.S. You guys at WetWebMedia are the most knowledgeable people around and thanks for all the help you provide. <<Other "knowledgeable" folks about, but thank you for the praise. It is our pleasure to help. Eric Russell>> Re: Pink Cucumber 7/20/06 Dear Bob, <<EricR again>> After scavenging around WetWebMedia I found that the squishy feeling is not a good sign. <<Okay>> So being scared for my fish I put it in a quarantine tank. After removing the Cuke I found that it became extremely hard again. The feather like tentacles retracted into the body and everything seemed normal like when I bought it. <<Yes...pumped up with water when it was disturbed>> Was everything normal and I just removed him for no purpose and just stressed it and myself. <<Is a possibility>> If I take the precautionary approach, how long should I keep the Cuke in quarantine and is there any non-stressful way to reintroduce it to my main tank without cutting off a lot of feet. <<You can keep it there for a week or so (be sure to target feed!) until you're comfortable with returning it to the display. As for removing it...be very gentle and take your time to SLOWLY coax it away from the glass. I find very light but persistent pressure from my fingers will usually cause the cucumber to release with no/a minimum of damage to the tube feet>> Thanks again. Jason <<Always welcome. EricR>>

Sea Apple - 3/6/2006 My sea apple had something orange coming from its butt what is this and what should I do? <<There is no information to go on here, so I suggest removing the Apple to QT, keep your water quality pristine, and watch. Sea apples are notorious for fouling whole systems, so removal ASAP is recommended. Lisa.>>

Sea apple... disaster - 03/05/06 My sea apple has some type of orange string coming out of her "butt" what is this? What should I do? <Carefully, and I mean with utmost caution, remove this animal INCLUDING this material. Please see here: http://wetwebmedia.com/cukecompfaqs.htm Bob Fenner>

Allelopathy, Cuke 2/1/06 Several questions real quick... I have e-mailed you twice with no response, so I wont put a lot in this e-mail in case something happens. If you need more info, please ask :) I have had a Cuke, (Cucumaria sp., family Cucumariidae, order Dendrochirota....pink and green cucumber) for over a year. It was placed in a 150 gal reef set up. It has been doing wonderful! It was feeding normally, etc. I had to do some rearrangement with the live rock in order to add new....that was about 3 weeks ago. Ever since I had done that my tank looks depressing. You know, just the feeling that something isn't right. Water quality was good....tested more than usual just to be sure. My Cuke began looking very different from what it had. It typically had a very strong shape, it's tentacles would extend fully while eating et al. It has its spot up near the top of the tank right beside the current. With the movement of the current it still held strong.....until therearrangement. It looked like a gooey mass of pink and green with its tentacles barely protruding, one may extend fully. The current looked like it was going to wash it away into nothing. Then it began to shrivel up, looking no bigger than the size of a little pinky finger. The color began to fade and still is. I didn't want any toxic nonsense to take place in my main display, so I moved it last night into a 20 gal set up. The color is still fading and I don't know what is taking place. Have you heard of this happening, and is there any advice you could offer? <Mmm, I think you were smart to move this animal... though as a species it is one of the more innocuous...> I guess I lied about this being quick, sorry.... along with my cucumber's odd behavior.....after I did the rearranging, some of my corals took a beating... I had 10 colt corals, ranging in size (just beginning to grow, to big and beautiful) that died....every single one of them died! <! Their demise is very likely directly related to the lapse in health of the Cucumber... and more> *sigh* the lessons I shall learn. And I had a leather coral which was about the diameter of a baseball...it had had a spot in the center that wasn't doing well to begin with....it is still alive but I don't think it is going to make it...it looks worse, one side may have the chance to make it, could I cut off the dying part or would that cause more stress? <I would move it to another system... stat! If you have one> If I did remove that part how could I go about doing that? <Covered on WWM> Did I witness allelopathy in my tank?! <Of a sort, yes> I am not extremely familiar with this, but I think I've got the gist of it....If there are any resources that talk more about allelopathy could you please refer me to them or tell me of any known websites. Thank you, and sorry for the super long e-mail!!! <This phenomenon is all around us... and a part of every system... and gone over and over on WWM. Put the term in the Google search tool... Bob Fenner>

Sea Cucumber In A Reef Tank? - 11/30/05 Sorry, I can hear the groan from here! Yes it's another fool considering adding a sea cucumber to his reef tank - it seems from reading through some of the FAQs on the subject I'd be better off adding a 3 bar electric heater James Bond style to my tank,( "Shocking..."), but I thought I'd ask any way! <<Hah! Not at all...I have a couple Holothuria floridiana in my reef...great little detritivores/sand stirrers.>> A friend has had a yellow cucumber for a while now and it has split into 2 and he has offered me one of his clones. I am still trying to find out exact species but I suspect it is Colochirus robustus. <<If a filter-feeder then yes, likely so.>> How does this species rate on the wipe-out front? <<Not as bad as many...I would add some to my tank but for my Copperband Butterfly.>> Also some more information on it's general requirements would be appreciated. <<Mmm, plenty to eat...lack of aggression from fishes...try a keyword Google search on the net for more detail.>> One of the FAQ answers seems to be saying that some of the smaller species, of which I think Colochirus robustus is, were not the time bombs their larger cousins are. <<Indeed...but some consider even the more toxic Holothuria species to become less so over time in the home aquarium.>> My tank is set up as follows: 5ft by 2ft by 18" tank. 45kg of live rock, 10kg of lava rock - water contents 340 litres after displacement. I have only a cosmetic sprinkling of coral sand on the tank bottom. <<Mmm...A DSB and/or in-line vegetable refugium would be beneficial to keeping Colochirus robustus...something to consider.>> Deltec DCE600 skimmer, Fluval 404 external, Rainbow lifeguard fluidized-bed filter, 4 circulation power heads turning over approximately 3500 litres per hour. Tank has been set up for almost 7 months. SG 1.024 pH 8.2 Phosphate 0.25 mg/l Ammonia 0 Nitrite 0 Nitrate 25 mg/l Ca 450 KH 161.1 ppm <<I hope that's 16.1...and still a bit high>> Fish species: 2 Pomacentrus alleni 2 Amphiprion ocellaris 1 Ecsenius midas 1 Neocirrhites armatus 1 Centropyge bicolor Inverts: Various red and blue hermits 1 Lysmata amboinensis 1 Stenopus hispidus Various turbo snails. Corals/Anemones: Sinularia sp. (possibly flexilis) Sarcophyton sp. Various Zoanthus sp. 1 Condylactis gigantea Various mushrooms Any advice appreciated, even if it is of the "don't touch it with a barge pole" variety. <<Not at all. Do your homework/provide for the welfare of the Colochirus robustus and you too will likely have it reproducing in your system.>> Thank you for your time. Bob Mehen. <<Regards, EricR>>

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>

Echinoderm Aggression (6/23/04) Hello again kind Sirs, <Steve Allen here.> Yesterday I added a Tiger tail Cucumber to my 45 gallon tank (50 lb LR, 5" DSB). Initially he seemed to settle in just fine. I got up a little while ago and took a quick look into the tank. My 2 brittle stars (6''and 8" mottled brown in color) looked like they were trying to pull the Tiger tail Cucumber to pieces. <They probably were trying to eat it. Perhaps they're not getting enough food.> I have never seen this kind of aggression from them and I've had them well over a year. <It does seem odd.> I see no visible damage (yet) to the cucumber but he was definitely having a rough night and it looks like he might have released a little bit of innards. <Uh-oh> I pulled the Brittle stars off and removed the cucumber then placed him into a 5 gallon quarantine tank, <smart> which just has some LR rubble in it. Tomorrow I plan to do a 20% (6 gal.) water change and also change out some of my carbon. <Wise. PolyFilter is useful for removing contaminants too.> How toxic are Tiger tail Cucumbers? <Hard to say. Less than say, sea apples.> Should I be more aggressive with the amount of the water I change? <If everything in there looks good, I doubt you need to get too aggressive as I would have expected a rapid negative effect right after the event. These toxins are fast-acting.> The next thing is I have to figure out what to do with the cucumber. I was planning to install a hang on refugium tomorrow would keeping him in there be an option, I know I'm reaching, but I thought he was pretty cool. <Nurse him back to health in the QT. See if feeding your brittle stars small chunks of shrimp or squid keeps them away from him. I suspect there was something wrong with him in the first place that led them to "attack." I would not expect your average Brittlestar to try to eat a healthy sea cucumber.> Do you have any recommendations on "stocking" the hang on refugium (19"x 12" x 4 ?"). Based on the picture in Reef Inverts (page 66) I was thinking of 1 inch crushed coral plus 3 inches of Carib special grade sand, some LR rubble and then ordering some macro algae (not Caulerpa). <Don't mix sand grades. I'd suggest 3-4 inches of sand and some LR chunk. Chaetomorpha would be your best bet, but I have successfully grown Gracilaria in my AquaFuge. Check www.inlandaquatics.com for an excellent selection and great service. This will make a great environment for 'pods & mysids.> I also have 10 lbs of LS coming in tomorrow (great timing huh) from Walt Smith which I was going to split up between the refugium and the display tank. I was also planning to add a couple of Ceriths and Nassarius snails to the refugium, thoughts? <Small Strombus snails are nice as well and will reproduce. Check www.ipsf.com> Once again, thanks in advance for the guidance. Chuck <Hope this helps.> Butterfly eating a cucumber Hi guys. Let me quickly say first that I am a huge fan. Your website and published material are a magnificent resource - unparalleled, to my knowledge. Furthermore, individuals of your caliber are a credit to the species; your very existence is sublime. Now that I'm through gushing, on to my question. I recently inherited a well established 200 gal reef tank. It was my fathers before me and although I always had a hand in things, I've only recently gotten creative control. One of the first things I did was introduce a pair of Pink & Green Sea Cucumbers (Cucumaria sp., I believe). I'm well aware of the potential danger they pose, but I've loved Holothuroidea since childhood and I simply couldn't resist the chance to finally have some of my own. So far, they seem to be doing quite well. I did a fair amount of research before and after acquiring the pair and have every reason to believe they are quite happy. That is, accept for the following. Amongst others, the tank contains a Butterfly Tang that's been with us for quite some time. My father was very fond of this fish (despite the obvious) and I would hate to see anything happen to him, so I became a little worried when he took a chomp out of one of the cucumbers. Fortunately, nothing catastrophic happened. Having read your Cukes guide I assumed it was an isolated incident: "Only the very hungriest and naive fish will (re-)try chomping on a Sea Cucumber." However, he seems to have developed a taste for them! << Very odd. >> Whenever they expose their tentacles to filter for too long, he'll take a bite out of one! << Oh I gotcha ya'. Yah I can see that happening. I wouldn't worry much about it, and would hope the Cuke learns. >> It goes without saying this has me quite concerned. I mean, sooner or later won't one of them simply get feed up and napalm the whole jungle? << Well that would be terrible, but honestly I've never known anyone who had that happen. >> Baring that, won't the Butterfly get sick? << I don't believe so. Here is why. If it is indeed toxic, logic would say he'll stop eating them. I think that may just happen. >> I feed him plenty, so I doubt he's doing it out of hunger. In any event, what do you suggest? << Nothing really. I think you leave them be and see what happens. I don't know if there is anything you can do. >> I've been keeping the cucumbers alive by supplying them with plenty of liquid plankton whenever the Butterfly is busy feeding on his usual frozen favorites far from the Cukes corner. << Great idea. >> Speaking of which, is it possible to over feed them in this way? << No, and live phyto is always good for the rest of the system as well. >> Not that I could ever distract Madam Butterfly long enough to do so, but I could happily watch them stuff themselves all day. Anyway, I sure could use some advice. I really don't want to get ride of either party, but is there anything else I can do? Thanks for your time. << Just let them work it out. >> << Blundell >>

Cucumber & Crab Question Hello Bob. I was just reading over your "Crabs for Marine Aquarium" article trying to ID a little guy I found hitchhiking on my new Tigertail Cucumber; low and behold, it would appear you've encountered this precise situation before. Apparently, I have a Lissocarcinus sp. just like the one in your photo (from N. Sulawesi). <Neat> Although I can not tell for certain from the image, it appears to be the same kind of cucumber. The crab seems quite intent on staying with the cucumber both in your photo and my tank. Thus I am very curious about the relationship between my two new guests. Would you happen to know more about it? Is it perhaps symbiotic? Parasitic? Or just a coincidence? Thanks for your time. <Very likely this is more of a commensal to mutualistic relationship... with at least the crab benefiting (getting towed about, likely avoiding some types of predation) and not harming the Cucumber host. Bob Fenner>

Cucumber and huge worm compatibility Hello. Me again. Sorry to keep bothering you, but I've just made what might be a relevant discovery pertaining to the matter about which I have sought your esteemed aid. After writing that last email, I went to go check on the Tigertail (it is presently night time here) and was shocked to find a monster of a Bristol Worm on top of him! Now, I don't use the word monster lightly: the exposed part of this worm had to be at least a couple feet! Although it moved very rapidly back under a nearby rock from which it had extended, the thing was so long I got a pretty good look at it. I think it was a Hermodice canunculata based on your pictures, or perhaps just something closely related. I've noticed smaller versions (a couple inches max) living in some sort of plant ticket in turn within a small forest of Spaghetti Finger Leather Coral. The Leathers have always been quite boisterous, so I assumed they weren't the kind of Fire Worm I had to worry about, but now this monster seems to have taken an interest in my cucumber and that has me worried.
<< I usually don't worry about worms. But if he is that big, I guess removing him isn't a bad idea. >> I know this to be true because after first spotting him, I left the tank dark for about thirty minutes before returning to again find him atop the Tigertail. I repeated the experiment a second time, just to be sure, and sure enough, he was back. So, what do you think? Should I invest in a trap or might this just be some sort of zany coincidence?
<< I'd just pull him out with some salad tongs. But don't tell your wife. >>
Oh, also, the Tigertail has a little passenger - a Lissocarcinus sp., I believe. Bob said the crab was no threat, but might the worm be after the crab instead of the cucumber? << Yeah a worm that big is big. It may be best to just remove him to be safe. Although you may have dozens of worms that size in your tank. >> Any insight you might provide would go a long way to puttering my nerves at rest. I've already named the Tigertail and am determined to see him live a long, happy, monster-free life. Thanks << For a trap, I'm impressed with the traps people make by folding up that checkerboard style craft plastic. The just fold it up and put a piece of shrimp in the middle. The worm wiggles its way into the plastic mesh, but can't get out very fast so you can just lift it out throw it away. >> again...again. << Blundell >>

Sea apple eviscerated... I'm forwarding you my UseNet question because I was told you may have an answer: Anyone know how to best care for a sea apple that has eviscerated it's internal organs. The tank is fine, the water isn't polluted with any chemicals that seem to be stressing the other inhabitants, but the poor apple looks to be in bad shape. the organs are still attached because no one seems to know if I should remove them. Any suggestions would be a great help. Thanks for any help you can provide, Dave P. >> Do move the animal into separate quarters... and don't attempt to remove any of the eviscerated mass... It may be re-inserted... but you don't want it dissolving, breaking up in your main tank. Bob Fenner

Sea Cukes the reef relief packages offered by FFExpress contain sea Cukes, should I opt for something else or are these Cukes safe? also are there any other animals that will eat or remove detritus from sand? thank you. <Most of the very small species of Holothuroids sold for this purpose are relatively safe... and there are many other choices... Please see the "Sand Sifters, FAQs" section on our website: www.WetWebMedia.com Bob Fenner>

Cucumber: Good news & Bad news.... Good morning Bob, hope all is well with you. I have been using the method we discussed with setting up my water changes a week before I do them, and that is working out very well!! I can see the difference in my corals, too. Everything seems to be much better off for not using the water conditioner. Thanks for your help with that!! <Ahh, very good.> But now I have another concern. I have either heard or read someplace that Sea Apples can kill off your whole aquarium if they happen to die in there. <Yes... in point of fact, they don't even have to die...> I have what was sold to me as an "Australian Sea Apple". Everything was fine with this animal until 2 days ago, when it got accidentally burned by my heater. It is a pretty good burn, too. The site has flaked off and is hanging. It's up near where he opens up to extend his tentacles. He got burned once about a year ago, and healed up fine but he managed to do it again to himself. I'm concerned about the rest of my community if he doesn't make it. Is this a valid concern?? <Yes, a valid concern... is this Cucumber large? Red, white and blue? Please read over the section on Sea Cucumbers, and compare the images placed there on the site: www.WetWebMedia.com> I have since purchased a new heater, one that is shrouded to protect the animals, and is controlled with a remote thermostat. <Very good> Thank you for your time!! Pat Marren <Do read over the WWM site and associated FAQs, and keep an eye on your other livestock... especially the fishes... will show dramatic and quick changes in behavior (gasping), swimming erratically (at first, last...)... I would move them (the non Sea Apple livestock) IMMEDIATELY if you observe this... Bob Fenner>

Re: Good news & Bad news.... Sea Cuke Bob, the one I have is just like the one first pictured on your web site, the red white & blue one. it is a pretty good sized one, too. Should I panic?? What should I do with it???!!!! Pat Marren <No panic... but I would trade it in... too much potential for a large problem... have seen this species take out many, many systems. Bob Fenner>

Re: Good news & Bad news.... Hmmmmm......do you think in it's injured state that it's liable to poison my tank?? It is moving around like normal and extending it's tentacles to feed. I am really concerned about this whole thing. Do you think he's in pain?? <No pain... these animals are absolutely amazing in their regenerative properties... as you might imagine... what else could they do if some animal wanted to sample them? Swim away?> Hey, how would you like a slightly used sea apple.......free!!!! <Oh no you don't! Thanks for the offer though. Bob Fenner> Pat Marren

Cucumbers Hello, I recently purchased a pink and black cucumber and 2 impatiens cucumbers from FFExpress. I then came across an article that cucumbers can expel their guts and kill all the fish in a tank. Does this apply to all kinds of cucumbers? <To a degree yes.> Are the ones I purchased safe? <Much more so than the few of their kin that are many times their size (the so-called Sea Apples in particular)> I definitely want to keep fish so if there is a chance of them expelling their guts and releasing poison then I might just remove them. Thanks for your help. Cathy <I would leave these in place. If this system is any size (forty or more gallons) and adequately filtered, circulated and the tankmates not likely to "bother" these Cukes there is acceptably small chance of a problem here. Bob Fenner>

A little extra help Hello Mr. Fenner! I love your web site! About three hours ago I asked for some help on WetWebFotos and got a few prompt responses. I love that site too!! <Yes. Very kind, involved people, with much to share> I asked about my Sea Apple. I know, I know, bad choice. I know that now! Read all that was written on your web site. If you could read my post (under 911, only post, I'm XBranX) and tell me what you think I would be grateful. It's not necessary though. :) I am writing you to ask if there is some fish/invert./coral that must come with a warning to the retailer? <None that I know of.> I don't think my LFS knew of the potential danger when they sold it to me. Maybe I am deluding myself. I am just wondering if the livestock they get or that they sell must come with some sort of warning? I hope I explained myself well enough. Thanks for a wonderful site Brandon <Thank you for your kind words. The "nature" of the industry is that there is so much to know, so little time, so few opportunities of effective communication that "what we all know collectively" is enormous compared with the intersection of what most folks in the trade know individually. The "average" (mean) marine hobbyist is in the interest for less than a year... retailers less than two... said but so. Bob Fenner, who hopes the Internet will come to be an important, easy, inexpensive, fast vehicle for solving such ills/shortcomings>

Pseudocolchirus oxiolugus I am looking for any info on the Australian sea apple Pseudocolchirus oxiolugus I have found next to nothing on the animal. Can you help me out? thanks Brian <A risky choice for pet-fish use. Please read re this and related species of Sea Cucumbers on our site: http://WetWebMedia.Com/seacukes.htm And related FAQs page. This species goes under other scientific names btw. Bob Fenner>

New and Misadvised Hi Robert, and thank you for tanking the time to read my mail.. <Jason... Anthony Calfo here, answering Bob's mail while he has been away in the far East perfecting his new found love for expressing himself through the performance art of belly-dancing> I am new to the salt water hobby, but I am very excited, and trying very hard not to get discouraged, but lighting my tank is making it very hard. <hang in there, bud...really no big deal> Right now I have a 75 gallon tank, that has a pink and purple tip anemone, carpet anemone, and a Sebae anemone. <new problem... anemones are very hostile/competitive with each other (allelopathy). The may look fine for some months, but be assured there is silent warfare going on. Mixing different species in the same tank is fatal to one or all in the two-year picture or sooner. Especially with a tiger like the carpet anemone... well documented. You must separate these animals in the near future in my opinion for their optimum survival in captivity> I also have a sea apple cucumber, <Jason... fire whoever told you to put a sea apple in your tank and perhaps insult them (joking) if they were the same counsel who suggested that you mix anemone species too. Sea Apples are VERY difficult to sustain and one of the worst animals for a beginner. It is unethical or at least inappropriate for this animal to have been sold to you. They may exude a toxin under stress (fish nipping, temperature increase, etc.) that can kill most or all other animals in your tank. I'm sorry to say. It sounds to me like you will be less likely to be discouraged in this hobby if you gather more information on your animal selections before you buy them. Kudos to you for trying so now. Keep up the good work... read some good books like the Conscientious Marine Aquarist and stop shopping at stores that regularly give your such shameful advice> star pulps, and brown mushroom's (which are doing well, but are definitely stretching for more light). <hardy and excellent choices> I also have some live rocks that are growing some other anemone like creature's, and some fan like thing's. Overall I think the tanks doing well. my question is with so many light out there what would be the best light's for me, I'm trying to put together a reef tank with both soft and hard corals. <but not mixed with anemones... a surefire disaster> I look at all these web sites and they have all these light's for five or so hundred dollars, there's no way I can afford that.. I'm looking for something around two or so hundred. <might be tough to fit that bill if your long-term goal is a reasonably well-stocked tank with hard and soft corals. You may have to wait on the inverts until you can afford the lights. Then... 400-600 watts of VHO or PC lights split between daylight and blue colors should work well for most beginner type corals> thanks again for your help in advance. any other pointers or info would be greatly appreciated. <very best luck to you... kindly, Anthony> sincerely Jason Schrecengost

Sea Cucumber Slough <Jon.. Anthony Calfo here answering for Bob while he is away in LA interviewing for a controversial new position as a male Victoria's Secret catalog model> one of the many cucumbers I have in my tank is what was said to be a hairy cucumber. it probably is since my LFS guy rarely makes a mistake. anyways, the question is do cucumbers exfoliate their skin? <sloughing is common particularly after a stress/move> the hairy cucumber appears to be 'shedding' its skin. I currently have a Cyanobacteria problem that is raging throughout my tank but the Cyano bacteria is dark red while the exfoliate is white. <entirely unrelated> it kind of looks like a colony of bacteria, which is why I mention the Cyano. regardless I took a turkey baster and gave it a few good blasts and removed most of the 'skin' which the mechanical filters promptly sucked up. <with the mildly to wildly toxic nature of various sea cucumbers, it is a bad habit to allow the noxious secretion to degrade in the system (the same applies especially to coral slough)... even if in a filter. No real problem expected, it's just not good husbandry> right now I'm thinking that its growing and doing a kind of molting. all of my cucumbers are fat on Cyano bacteria as of late. thanks. Jon Trowbridge <Rock on, Jon. Anthony>

Pink and Green sea cucumber Dear Mr. Fenner, I recently made the mistake of purchasing a pink and green cucumber (one that matches the picture of the two cucumbers that you have on the bottom of your cucumber page in which you stated more generally works out) before reading your page on cucumbers. Now that I have read it, I am sort of in a panic mode about their capabilities for wiping out an entire tank. How prone are these specific cucumbers to releasing their toxins, <Mmm, a possibility... should they be sufficiently stressed... and the system relatively small... and/or poorly filtered... water quality otherwise impugned...> and what should I look for besides spilling their guts out which are signs that they will soon release their toxins. <Not moving, discoloration, vacuolations (missing areas)... other livestock "acting funny"> Should I just get rid of it right now? <Up to you... see above and WetWebMedia.com FAQs on Cukes... a calculable risk> The place that I bought it at do not accept returns so it would just go to waste. Thank you. I look forward to your reply. <Could be traded with others...> P.S. FFExpress sells this as pink and green cucumbers too, knowing their dangers, why do they not put this cucumber on the restricted list? <Mmm, you'd have to ask them... All life forms have their inherent potential to "cause troubles"... some more overtly than others... Bob Fenner>

Interesting but Deadly Critters? Hello Bob/Gentlemen, <I'm not sure if I resemble that remark, but thanks kindly anyways...Anthony Calfo in your service> I have a few questions regarding a package of invertebrates that I am interested in adding to my 90 gallon reef tank. The package includes: - 2x - tropical abalones <most heinously excellent creatures...very good algae scavenger> - 2x - Mithrax crabs <OK> - 1x - impatiens cucumbers (Holothuria impatiens) - 1x - tiger tail cucumber (Holothuria hilla) - 1x - pink and black cucumber (Holothuria edulis) <hello cucumberville!> - 1x - red Fromia star (Fromia sp.) <very good...Fromia are much better captives than Linckia species> I searched through your website for related articles and FAQ as well as other publications, and the consensus is the lethal potential of cucumbers "eviscerating" and then wiping out the entire tank. <ya... that is troubling> While I certainly do not want that to happen, I noticed you (Bob) cited in one of your FAQ that the species of cucumbers mentioned above have a lesser potential of eviscerating. <have you never been a victim of Murphy's law? Hehe...> Having said that, should I go ahead and purchase the cucumbers or eliminate the them from my selection? <if you do not have a distinct passion or need for sea cucumbers, please don't bother to take the risk. There are plenty of other detritivores out there. For simply diatom reduction and sand sifting...consider a goatfish, they are great and very underrated > Secondly, with regard to the red Fromia star and Mithrax crab, what is the likelihood of them bothering/eating my corals? <low risk...worth it if you like. Although the Mithrax are not the most diligent members of any janitorial crew> Lastly, will the above mentioned livestock cohabitate with my existing livestock? Tank Conditions: - Inhabitants include: yellow tang, purple tang, male flame wrasse, 2x - female flame wrasse, an assortment of soft and hard corals, black brittle stars, cleaner shrimps, snails, and hermit crabs. - Water parameters: Spg - 1.026, carbon hardness - 10dKH, calcium - 420 ppm, ammonia - 0ppm, nitrite - 0ppm, nitrates - < 2.5ppm, phosphate - < .03ppm, magnesium - 1350ppm, temperature - constant at 78 degree, and pH - 8.2 (this may be attributable to my calcium reactor, the CO2 could be suppressing the pH value). - Filtration: 120 pounds of live rock, and a hybrid 30 gallon ecosystem/ETS skimmer sump. <compatibility is likely to be fine...but the pH is indeed a bit low. A very beneficial and convenient correction for this is a second media reactor for the effluent of your calc reactor. Tempers the pH and maintains extraordinary alkalinity> My reef has been running well for the past two years; I wanted to add the above invertebrates for interest and maintenance values. I want to thank you in advance for your time and effort. Your website is a great value/tool to all hobbyist to learn and share! <thank you very kindly.. and for what it's worth, a second skimmer and/or better water flow would negate the maintenance needs of such a minor crew of detritivores. Anthony Calfo> Best, Dan

Poisonous Invert questions Hi, Thanks for the wealth of info on your site! I have learned so much while researching for my first marine tank. I plan on setting up a live rock/small fish/basic invert system. (No corals of anemones) I love sea cucumbers, but everything I have read about keeping them has discouraged me from getting one. Are there any species available in the aquarium trade that wouldn't pose any threat to my whole system with poison? I've heard some real horror stories about certain kinds! I'd sure like one, but don't want to worry about poison/toxins. <honestly a hard question to answer fairly... poisonous animals don't go about the everyday randomly squirting toxins around (unless we are talking about gaseous Homo sapiens co-workers that drink too much beer). So even the toxic sea cucumbers in this case are of little risk if you plan the tank sensibly... protect pump intakes, guard from aggressive or inappropriate tank mates, maintain good water quality, etc.). And so, without triggers or attempts to pass them through the intake strainer of a power head you have little to worry about. Indeed, they are somewhat more of a risk with consideration for random unforeseen acts (3 day power outage, failure of heater/chiller... although this can be shored by extra heater, cheap alarms (even inexpensive ones like x-10 modules that can call you if the alarm is tripped), etc. So how much of a risk with toxins are you willing to take to keep mandarins, Soapfish, boxfish, sea cucumbers and more? Long story short... the "safer" sea cucumbers are the less colorful ones. Specifically... sea apples are more toxic. And by the way... not all sea cucumbers are sea apples but all sea apples are sea cucumbers. Hmmmmm? Yes, do pursue the less colorful species and research their husbandry as well...some are detritivores that need very fine sand, some are filter feeders (tough to keep usually)> Lastly, I would love to include a pencil urchin in my tank, but have recently come into info that they too can release poison into your system. How likely is this, and how much potential threat could they cause to a small tank, say around 40 gallons or so? <I have not read that common pencil urchins have any significant toxin if at all. They are known to be extremely safe even if killed or dead in aquaria regarding some so-called toxin. Keep in mind though, that this is one of the few Urchins that is not largely herbivorous! They need meaty fare to survive> Would it be wise of me to avoid an urchin due to it's poisonous abilities? I would prefer to avoid any worries with poisons in my system. <you may need to avoid most or all sea cucumbers then. The poisonous urchins by the way that I am aware are not slate/pencil species> My apologies if I overlooked this info on your site, and thanks a bunch for your time! Jeff Rogers <best regards, Anthony>

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