The oscar
Jexnell
sent me was mostly white when she was a baby. He can post pics of when she was little. Their color patterns do increase as they grow. I know feeding krill will bring up reds in a lot fish.
Os need a pretty varied diet. I feed mine hikari carnisticks, Repashy gelfoods, krill, market shrimp, pealed grapes, and the babies like fuval bug bites pellets. For live foods I use night cralwers, crickets, small crayfish, and ghost shrimp. Most people here will steer you away from using feeder fish. There are multiple cons and few pros to using them.