Keeping Cukes And Keeping Them From Cuking And Damage Control

[gregswimm]

Got a holothuria hilla or floridana a few days ago. I had done much contemplating before this purchase about whether or not I could feed one of these guys for an extended period of time. I run a skimmerless and media-less (for the most part) 29g so I should be able to keep enough dirty sand.

As I write this I see a a peppermint shrimp come running from one side of the tank and begin picking at the face of the cuke. Which brings me to my question, I my cuke does eviscerate is there any amount of GAC I can keep running in my tank that will save my livestock for a few hours (9h max) till I can do water changes etc.?

Ya... the peppermints will go back tomorrow, they have been somewhat problematic (I have 2 one of which is with egg, If you want them PM me before 1PM EST). We do not mess with the cuke, the cuke will kill you then it will kill your family....

A pic of the holothuria:
(that's a face only a mother could love)

 

[crazyforcordoras]

Actually, holothuria do not posess toxins. I had one in my 10 gallon for a while and when it passed, nothing died. I then read that they dont have toxins. It wuld be nice to give up the peps. Mine would also pick at the cukes.

 

[gregswimm]

Ty donya, you are awesome

 

[Donya]

Actually, holothuria do not posess toxins. I had one in my 10 gallon for a while and when it passed, nothing died. I then read that they dont have toxins.

Plenty of members of the genus Holothuria carry toxins. Otherwise people would not be doing studies on this stuff giving titles like these...

"Effects of the Crude Toxin of Sea Cucumbers Holothuria atra on Some Hematological and Biochemical Parameters in Rats" - Mohamed A. Zaki
"Relaxing action of a holothurian toxin on mammalian smooth muscle" - De Vore DE, del Castillo J.


Where on earth did you read that the genus has no toxins? Death does not mean automatic toxin release. Usually toxins are an issue if the animal is injured (in which case it almost certainly will die anyway) or harassed by something else in the tank. Some are suspected of being able to release the toxin into the water (or it gets into the water from the act of injury shredding tissue and such) and for others it may be that expelled organs have to be nibbled at for fish to experience side-effects.

Which brings me to my question, I my cuke does eviscerate is there any amount of GAC I can keep running in my tank that will save my livestock for a few hours (9h max) till I can do water changes etc.?

I'm honestly not sure off the top of my head whether these are one of the ones where the toxin release has to be because of the organs being shredded by something. Even if it's only in the organs, if such an organ got sucked up into a powerhead, nothing good is going to happen even with GAC present and it would be a gamble. I'll have to look in the literature I've seen on them but I have to run in 5min so I'll have to do it later. Please bump the thread or something if I forget. It may be that in the past I found nothing conclusive on those, but I can't remember.

 

[Donya]

Thought I'd read of fluid release before...found it.

Rough handling underwater in the laboratory tanks stimulated Holothuria atra, H. hilla, and H. cinerascens to contract and swell similarly to the responses described for each species. Also this handling caused a reddish fluid to be given off by H. atra.
(...)

Holthuria hilla seems to have little defense against tonnid attacks; every attack resulted in the death of the prey. Quick retraction of
the body back into a hole or crevice may be a successful way to avoid an attack.
(...)
The principal defense of Holthuria atra to tonnid attack is probably its large size coupled with its secretion of holothurin. When handled roughly this species gives off holothurin (Bakus 1973).

from "Responses of Five Holothurian Species to Attacks by a Predatory Gastropod", R.K. Kropp, 1983, University of Hawaii Press.

If H. atra can do this I see no reason to assume that other Holothuria species are safe in that regard. This is not to say that there won't be some that don't or can't, but rather that I can't find any sources that specficially say "X can't secrete it," so one has to assume that it's a risk even if a small one. The passage above seems to suggest that H. hilla is at least incredibly unlikely or unmotivated to do this, but it is only describing one type of predator. Different reactions could easily occur if something else happened, such as a rock falling on the animal. There is also the issue I mentioned previously that if a holothurin-containing organ gets expelled and pulverized, it's as good as the animal having secreted it.

In the event of such a release, in a small environment bad things are going to happen to fish if the quantity is large enough, so you'll be looking at a concentration issue rather than a chemical filtration one since the water isn't going to be immediately passed through the chemical media from all regions of the tank. If you've got any fish that you absolutely can't bear to lose under any circumstances, I would take the cuc back since it is not a risk-free animal, particularly while there is no certain ID. If you keep it, you'll want to protect the powerheads with sponge, floss, or really fine mesh (such as 1mm holes) to avoid the risk of cuc soup.

Regarding the exact ID, I don't think this one is H. hilla. It could even be H. atra if you don't know the collection region.

 

[crazyforcordoras]

Well, at leats the ones i had didnt. They looked like that one too. Sorry

 

[gregswimm]

I have no fish, and don't plan on getting one till I hook up a sump. The only thing I would be upset to loose are my sessile inverts (corals and clams). The cuke is just soooo useful and has been diligently gobbling up my nasty sand.

The LFS said it was collected out of the florida area so im leaning toward H. floridana. I recognized it as a 'tiger tail' but I hope they were right about the FL collection. If it is the atlantic variety, no bueno; I have seen them get over 3'.

I read somewhere that the holothurin is in their blood giving it a yellow color.

Here is another shot, cleaned the glass (sorta) this afternoon

 

[Donya]

If it's definitely western Atlantic or gulf then it could be H. floridana...I've unfortunately got no trustworthy sources describing that one. Some time ago I even sought help once with an attempt to confirm or rule out H. flrodiana on a cuc and nothing useful turned up. The black feeding tentacles are a little weird, but that could be within the range of variation. Finding good references for IDs beyong the genus on some of these guys is hard.

The only thing I would be upset to loose are my sessile inverts (corals and clams). The cuke is just soooo useful and has been diligently gobbling up my nasty sand.

These should be ok. Some of the main predators of cucs are snails and Crustaceans because the toxins don't work on most inverts, so I would assume other molluscs are ok. All of the sources I've got point to the toxins being pretty vertebrate-specific. It's not impossible that an invert out there might be affected a bit, cucs are pretty widely considered invert-safe.

 

[gregswimm]

Sweet! Lets hope your vertebrate only prediction holds true.