First off, it is not uncommon at all for male rosies to shut off like yours does. It is often a sign of sexual maturity for a male rosy to eat like bonkers for brief periods in early Spring and Fall but refuse food the rest of the time. You said its a '00 and its eating pinks?? I would feed him a decent-sized meal at least once a week while he's eating. Can't you get something bigger than pinks?