What Cecil said is accurate in my opinion and experience. Probably the most aggressive species of fish I have raised had been red devil cichlids. Those things are just plain nasty. You stick your hand in the water and they will attack it. Especially if you put it near a nesting pair.
I am not sure anyone has written literature on RES in aquariums and what does and does not precipitate aggression. My experience with RES is they are middle of the road for aggression when it comes to sunfish. My experience is most species become more aggressive in general when exposed to live feed. If just fed pellets, they are less aggressive. I do not have enough experience with RES to say if this holds true for them or not.
I can say, success rates of RES preying on FHM in an aquarium setting would be substantially higher than in a wild environment such as a pond.
