What is this?

[mcduff]

I got my LR from Florida. What is this in the middle of the pic. I remember when we go down to the Keys, I would see these when we snorkel. We used to call them sea terds

[Cytosol]

Does it move around? I would guess sea cucumber.. Something from my experience you don't want in your tank because when they die, they dend to take the rest of the tank out with them.

[Cytosol]

Upon further thought, this look like a Black Knobby cucumber.. Which is great at tunneling through your sand and keeping it clean. I'm not sure if these release poison if they die, but I know some cucumbers and apples tend to do this even when stressed..

 

I had a sea apple in a tank like 10 years ago that decided to eject all of its internal organs out through its mouth.. and kill pretty much everything in my tank with poison. .. It then swallowed its guts again and lived for a bit longer before dying. Not a good thing to have happen!