Threads like these hardly ever remain peaceful. I agree with the majority of fish on the Top Aggressive list, except for a few like JD,Sevs,Oscars, and the small African Cichlids. But like everyone knows, there are always some that break the norm. I actually had a Psycho Severum many years ago that ruled the tank. But there are just some species that are more likely than not to be very aggressive. I think most of those have been mentioned. Tank space, stocking, and overall experience with keeping various cichlids will give people different results and ideas of cichlid aggression. One man's super aggressive JD could be bait in another man's tank. A lot of cichlids have the potential of being aggressive under certain circumstances.