i went through 2 curupiras, 3 reds, 2 golds just to find ones that get along.. the red chases the gold and vice versa sometimes.. there was a gold in there before that messed up the red and almost killing him, if u look closely the reds tail is messed up. It still not fully healed. Had to sell that Gold.. this guys are going in a 125g once they hit 8-9“. Reds are aggressive that is true, they kinda like to pick fights. I do have back up tanks for each of them. theyre still juvies, curupira tend to be killers once they hit 10”+