Questions about Sea Cucumbers

[KleineVampir]

I got a sea cucumber about a week ago and basically he crawled into a rock and refuses to leave. Thankfully I at least still see him since his head is always poking out. Can he eat without going onto the substrate? He doesn't seem to be the filter-feeding type of cucumber. Is my substrate too coarse for him to want to eat? It's a little coarse but my sea hare can pass it just fine...then again the hare is bigger. This cucumber is a little small.

The other question is: Is this cucumber really that risky for me to keep? I have a lot of snails, 5 fish and a crab. Nothing super expensive but I still wouldn't want them to die!

Let me know if you want a picture.

 

[lmm1967]

details about your tank? Size, age, sand bed depth, what cucumber is it?

I have one each in 2 of my tanks. One of them (yellow) is fairly active and I see it routinely - at times out and moving about during the day.

My other one - a tiger tail - is in my 120 gallon and I rarely see it. I know it's there and doing fine because I see evidence of it working - piles of sand "poop" near the edge of rocks in the morning at times.

 

[KleineVampir]

It is a 40b, about 4 months old (but it's a 0 water change experiment so imo it's like an older tank.), sand bed is about an inch or two, and dunno what kind of cucumber it is. Probably a tiger tail or something similar.

 

[AlexG]

Sea cucumbers are typically most active at night. I have 7 in my reef tank and they have a minimal amount of activity during the day.

 

[KleineVampir]

I don't think he's doing a ton at night either. I mean I've gone in at night and he's still in that hole. More extended than usual though I think. Could he be eating off the top of the rock he's in? There would be algae right there above him. Will they eat the algae right off of rock? Cuz I don't think he's doing any sand sifting.

 

[lmm1967]

I can't answer those questions - but people that can will probably need a photo or determination of what type of cucumber you have.

 

[KleineVampir]

 

[KleineVampir]

I know it's not much but those are the pictures. That's as good as it gets with my phone!

 

[Bret Brinkmann]

Pictures of scardycats can be difficult. I wouldn't rule out a filter feeding species of cucumber. Especially if it sticks out something like the sea apples do.

 

[KleineVampir]

Pictures of scardycats can be difficult. I wouldn't rule out a filter feeding species of cucumber. Especially if it sticks out something like the sea apples do.

I don't think he's one of those though. I think he needs to eat detritus, and maybe algae. He doesn't seem to be doing much except slowly wiggling around in that hole.

 

[Gareth elliott]

They are not the most active of clean up crew. Which is one of their benefits in my book. Unlike other echinoderms that can deplete a tank of its food source cucumbers are slow. An unlike a sea star, they preform asexual reproduction if food is tight. Take one of these splits and gift or sell it. When they are in ill health they deteriorate quickly, tissue will flake off, think of your self with a sunburn. This is uncommon btw.

 

[malacoda]

Most eat minute detritus and bacterial film. Typically by ingesting sand, consuming the detritus and bacteria coating it, then pooping out the clean sand grains. However, they can also used the appendages at their mouth to consume film off of rock.

The two Atlantic cucumbers (Holothuria (Thymiosycia) impatien) that I had spent their first 3 weeks in the tank eating off of, and hiding in, the rock work before finally making their way down to the sand.

BTW - a little hard to tell for sure but that looks to be its anus in the picture, not it's mouth. My guess is it's slowly consuming bacteria and detritus that's inside that hole. (A bit of trivia - they breath and poop through the same hole.)

As for risk ... again, hard to tell from the pic, but it looks like a black cucumber or an Atlantic cucumber. VERY low risk. If it somehow gets chewed up in a powerhead, or really, REALLY stressed out by a predator it might release enough toxin to poison the tank ... but very, very unlikely. Two reasons:

1. IME, those types of cucumbers rarely climb the glass much.
2. I doubt you have anything in a 40b that would be big enough or desperate enough to prey on it.

Here's a good article if you want more info: https://www.advancedaquarist.com/2003/1/inverts

 

[KleineVampir]

Thank goodness. Now that was the answer I was looking for! I'm getting a gyre for a powerhead and supposedly they are pretty safe. The only thing that could conceivably prey on it would be the emerald crab...but there are so many snails constantly dying in the tank I think he is plenty busy. Not to mention the huge amount of hair algae in the tank.

Interesting that you would know the behavior of cucumbers like that. Sounds like this one's behavior is pretty normal/acceptable. Hopefully he can get the sand through his system though really it is like aragonite...not really a very fine sand.