I would have to say in my own experience trimac cichlids are the most aggresive. He beat the crap out of Jack Dempsey, and my dovii(though it should be noted the dovii was a female so could have been less agressive). He also attacked my red wolf fish from time to time. I had two trimacs since getting into fish and they ruled the tank. I only lost them cause a hurricane killed one and one died cause it litterally chased and beat the other fish until one day its face turned black and just stopped moving.
