What I mean by he enjoys sparring is he likes going back for more and won't let up despite taking quite a bit of damage.. I think now its mutual respect for eachother that's preventing either of them doing even more damage.
I see. Really, what other option does the fish have in that situation? They live in a small box of water with other fish that , by nature, have the same temperament. Ultimately the purpose of the aggression is to establish boundaries and discourage other fish from infringing on breeding areas. From what I saw of the tank in your video, that encompasses both. At a minimum, give them more area for cover. I think breeding results would actually improve if the fish could dedicate more time to that process rather than an ongoing onslaught with the tank mates.