sea cucumber in trouble

[mr. cheezle]

I have a black sea cucumber in my tank. He has been in there happily for 6 or 7 months. Today, somehow, he has a chunk out of him. It is about the size of a quarter and doesn't appear to be deep. The black skin that is missing from his body is on the tank floor. I don't know what happened. I don't think anyone in the tank attacked him, but can't be sure. He is still grazing along the sand as usual. My question is, do you you think he will recover? Or, do you think he will die and end up poisoning the tank? Any help, would be greatly appreciated.

 

[ophiura]

Can you post all of your tank parameters, inhabitants and tank size?
A picture may be useful.
In general, yes, they can recover...but it depends on the causes. We need to eliminate some obvious causes.