As far as aggression he's not that bad, although he likes do duke it out with my little LM bass at times (never anything serious). Although the two of them have been stressing out my two rock bass lately, working on rehoming the rock bass.Green sunfish,most grow about 6 inches,but some grow to over 12. Can be rather aggressive.? They eat pellets,crickets,Phoenix worms, or basically everything's NGOs I've ever tried to feed them.