Definately feed the Oscar pellets. He'll eat them if he gets hungry enough. As far as feeders go, I would buy a pair or two of wild guppies. In a month you will have plenty of feeders and at the just the right size for a juvenile Oscar. As he grows and you still want to give him feeders, you could set a minnow trap and get your own or you can feed him crayfish, they love um. But, feed live foods sparingly, just to give the fish something to do predatory wise, like he would do in the wild.