Seems to be dominance/territorial behavior mate. Not that finnage is a clear indicator of sex, but the dorsal/anal fins on the "female" that Homer was harassing the most of the 2 are developing a male type look to them. I had a sub-dominant mikula in my previous group that, once the dominant male died, 1 of my "female" appearing fish became the dominant male. Not saying that is the case here, but it could explain some of the territorial aggression 




