One of my easterns almost always looks skinny. The others stay nice and plump........healthy and lookin great. The skinny one will eat just fine with the rest and then the next day he'll look skinny again. I feed them about 2-3 times a week, a varied diet of frozen blood worms, live red wigglers, strips of filleted / boneless herring, and frozen brine shrimp. he seems to act just like the others. any ideas??