Oscars are good. My personal fav. fish. But i would reccomend a Jack Dempsey, a Plecostomus, a Red Terror, and a few feeder fish just so if they do decide to fight then they will take out the feeder fish. If they choose not to fight don't worry the feeder fish won't last long. If they do i would reccomend flushing them so that it doesn't harm your tank, with the ammonia produced. Oscars are awesome fish, but you will need a heavy duty filtration to house cichlids period , but mainly oscars. If you don't introduce the pleco immediately you will be unable to and it will be killed soon after placement.