my 11" barred midas (very similar to flower horn) is extremely mean, she is so mean i cant have her with anything. i tried a 12" clown knife and a 16" pleco and she whooped up on both, and i had to remove them, she wasnt even acclimated to the tank yet either when i put the other ones in.
shes even more aggressive now, i cant even put my hand in the tank without her trying to thrash my hand. she pulls the fibers off the algae scrubber and she knocks the glass magnet off when it moves.
ive never, ever, seen a meaner fish.
needless to say, she has her own tank.