they won;t eat just anything....
%60-%70 of their diet should be greenstuff's (sea veggies, seaweed selects, or nori). the rest should consist of some meaty foods. i feed mine shrimp, clam, octopus, and squid and he really loves that stuff alsong with the nori.
you really need to feed these guys daily because their boney plates don;t allow them to hold large amounts of food in their stomachs. when you see the midsection start to look concave it means that he needs to be fed.
they are excellent fish, slow growing, long lived and almost like a "pet dog" in a tank once you get a handle on their feeding requirements.
good luck