it looks like a baby gorilla crab. carnivorous and very capable of killing smaller fish and inverts. i lost 4 fish to one of those guys before i figured out what it was.
I cannot seem to find a picture of it. Got any triggers? That would be fun to watch!! I googled it here is a search thread for them. http://search.live.com/results.aspx?q=gorilla+crab+pics&form=QBRE
I agree, it does look like a gorrilla crab, no matter there are very few crabs I want in my tank anyway, they detroy and kill things, especially snails.
