Anything wild caught. My wild caught oscars would go with anything in the tank guapotes, amphilious species, buttikoferri you name it. But as everyone knows it depends on the personality of the fish. But my opinion for top 3 would definitley be not in order, Emperor, Umbie and Dovii those 3 at full size have the ability to rip a lot of fish to shreads. My buddy had a 15 inch male Umbie that shared and more than held his own in a 200 gallon with a 14 inch male and 10 inch female mated pair doviis.