I have one swordtail that keeps getting chase by my platy every so often all over the tank both are males. I am 99% sure is because the swordtail keeps chasing after the female platy that the male platy chases. I know that both species of fish can cross-breed although I am not interested on it. Usually the male swordtail which is the only swordtail in my 60 gal tank stay on the entire left side of the tank at the top, but is active, I do have another female platy, but he doesn't seem to be interested in her. Now I am debating if I should get a female swordtail for him because something tells me he won't be interested, but I don't know really. Same can be said about my mollies which I have three one male and two females, but he isn't interested he stay on the right side of the tank towards the top as well. So is this aggression? Is it urgent to get a female swordtail for my male swordtail?