Alright i am about 95% sure i found one of these in my aquarium. It is under an arch, on the side of a rock wall. I read they are cool and what not, but also read that they eat fish, ingest corals, eat shrimp and all sorts of stuff. It is in a reef tank, is it good or bad?
Pics:



(and of course i get the ugly white one instead of the cool orange or purple.)