Generally, small fish need to feed at least twice daily, and juvenile oscars are no exception. I tend to only feed baby oscars until their bellies are slightly distended; that is called feeding satiation. Try and vary the foods a bit, even on a daily basis. For example, mysis shrimp in the morning and a staple pellet in the afternoon or early evening. Also make sure that you are offering a small amount of food at a time. Let the fish actually swallow some before you dump more in their tank. If you add too much, oscars tend to gum and spit their food in an effort to move on to the next piece that is offered. Basically it should take longer than 10 seconds to feed your fish. You enjoy watching your oscar, so take your time!