The one thing I hated about mine is that it constantly picked at the rock..Everytine I added new rock with anything at all growing on it,he would pick it totally clean as fast as he could..So you need to make a choice(as I did) do you want nice looking rock with stuff growing on it,,,Or the fish??? I chose the rock and eventually got rid of the fish....As for feeding,He ate anything I put in the tank.Frozen brine,Mysis,flake and pellet food...