I feed mine 1/4 " pieces of silversides, krill, and mysis shrimp. Anything bigger can stress it and result in later regurgitation, thus possibly causing a water parameter problem if you don't watch it. Maybe once or twice a week, but I'm trying to get him to grow (which he's doing by leaps and bounds). It's no big deal though if you feed less often as long as the lighting and flow is good, at least in a tank with fish in it. They get a lot of nutrition from that source too.