All will be agressive espicially depending on the tank size, in a 1000 gallon tank (Toledo zoo) I saw a breeding pair of Dovi in a community tank that kept themselves in a corner with fry but were not crazy aggressive but the tank was 1000 gallons. In a smaller 180 or whatever differant story. Dovi have large teeth so that helps to keep them as the top candidate. You take a fish out of a big lake and put him in a glass box and he will be aggressive because in the wild the other fish just swim away or avoid the agressor.