Poor little Athos didn't last long. I don't know what was wrong with him. He looked fine but he didn't hang out with the others and stopped eating today. He had no physical problems at all except for some nips on his tail and the fact that he was holding his anal fins kinda funny (straight down, not moving them). Today he was staying isolated by the bubble wand or staying at the top of the tank. I just flushed him.
I think I'll leave it for now. I don't want to add one new male cause I'm afraid he'll get picked on and these three seem to have things worked out. When I add more in a month or so I'll add three instead of two. :( Everyone else is acting perfectly fine and normal. *fingers crossed*