mine goes crazy during water changes. During feedings, he patrols the bottom like a little vacuum, stuffing himself with bloodworms. Very active once they get comfortable in a tank
I have never been able to stop that type of aggression once it has started. I would try taking out the decor and then rearranging the tank a few hours later. I don't want to say you need another tank, but maybe you will need to move one of them soon.