I think a lot of aggression with flowerhorn's have a lot to do with how they are kept. Majority of flowerhorns are kept in solitary from the time they are post fry stage and that is what they are accustom to. So when people try to throw a flowerhorn that has been alone all it's life into a community tank, it just doesn't know how to act. I had a flowerhorn in a community tank with 5 other cichlids and it was fine. I introduced the flowerhorn when it was only about 2 inches and the other cichlids were all around the same size. So if you're gonna do a community tank, first make sure the tank is big enough, then introduce them when they are still small.
I just brought home my first two flowerhorns yesterday. They are juveniles and are about 1 1/2-2 inches. Until I get their own tank up and running I have placed them in our 55g tank with a group of cichlids. All of the fish are approximtely the same size.
The flowerhorns continuously flare their fins and turn red and they CHASE the other fish. Anytime another fish is near they quickly send them away. They are VERY aggressive and are only babies.
I will be getting their tank up and running a lot quicker than I had planned.
if there still young you can keep them together, but it'll help if you throw in 6-8 parrots not to big for them to chase around, but big enough for them not to die, it workss try it, how many gal is ur tank?
An odd dynamic I've seen with FHs is if the female is near or equal in size to the male she tends to shred or dominate. I've often wondered why people paired full sized males with 'barely legal' females...this is probably why. A guy who used to own a family buisness fish store in the neighborhood said that had been his experience. Thing is there's no way to know how big the pairs will grow!