The other day I purchased a pair of platies, both female. But when I got home, I saw one of them was a much longer, streamlined shape than the other and was much more aggressive. I think she's actually a sword tail female. Anyways, she mercilessly chased the female platy around and stressed her out, so I took her out and she's currently in another tank. I was wondering if it was okay to keep them alone for the time being, or if I'd have to get them each companions of their own species..