I feed various foods, so they get used to trying whatever pops in the tank, for two weeks they'll get somthing different everyday, krill, mysis, bay scallops, shrimps, cat fish, etc (no live food though) and than one day I switch to pellets only once a day until they break the habit. some fish will hold out for days, but hunger beats them all, no fish will starve to death when theres somthing edible in with them. except wild black piranhas, I wouldnt put it past some of those bigger wild ones to possibly be unbreakable but for a LMB? it should take no more than this 3 week course on tuff love lol