we had a flowerhorn for a very short time, when she was sick she was very docile and got along with everybody in any tank.. after the good water and good food worked it's magic, she became mean and picked on everything and anything that was with her..
we sold her for $20 because i didn't want to dedicate an entire tank to 1 fish that i couldn't even have tank janitors in with.. she even tormented the cave dweller pleco..