Possible nudibranch, sea cucumber, sea hare, or sea slug ID?

[Koston]

I'm trying to find out what specifically this is. This is my post from over at Nano-Reef.

It's yellow, has some spikes on it (all of them are moving and a few sharper looking ones are black tipped), has a definite head with a lot more spikes/sticky up things, and a definite butt.

Moves kind of slow, found on a nassarius snail shell.

This is the second one I have found in a few months. The first one I killed immediately. Now since I realized there may be a bunch, I need to figure out what it is.

It looks almost like a yellow sea cucumber, like just the kind where you Google Image "yellow sea cucumber", not quite as thick like that, though...

Sorry if there is an ID forum for weird inverts, etc. that I'm missing. I'm new to R2R! Thanks everyone.

 

[SmokeyCFH]

looks and sounds like a cucumber to me.

 

[Troylee]

By that pic I would say its a nudi but not sure which kind... Most likely it's not good thou...

 

[sprinklerdudes]

+1 nudibranch, hard to tell

 

[Koston]

Looking for more opinions. I left it in a bowl of water on my desk and someone threw it out. This is my second time finding this exact guy though so I'm assuming there's more in the tank.

 

[sprinklerdudes]

I found somthing that may help on the id, was looking at reef2go website while ago,
they have a clean up crew pack, 100 ct, it has some good pictures in it,
one of the animals is a lettuce nudi branch, when you look at the pic you might
be able to make a better discission, just found this while ago, thought it may help

 

[Koston]

Oh, it definitely not a lettuce nudi. Thanks, though! I think it's a cucumber.

 

[Lateral72]

Does it have some rigidity to it if you were to squeeze it a little? Or does it feel like a pile of snot?

 

[Koston]

It's gone now but it felt like it had very little to no rigidity, definitely more squishy. I could crush it with no force at all, kinda goopy.

 

[Lateral72]

Definitely a nudi then, IMHO.