about 100%. some people say they will pick off small shrimp or fish, but i know several people that have them and i've never heard of them eating anything. They r small with very small mouths. I have cleaner shrimp,a pistol shrimp, a rosea pseudo, and a tiny pygmy hawk and he pays them no attention. I feed mine large mysis shrimp, thats about the size of food that he'll take, anything larger it won't touch so u could imagine how small something would have to be for him to go after it.