Lately I have been noticing my Mickey Mouse Molly chasing my Red Wag Platy. The Molly doesn't appear to be aggressive or nipping at the Platy. I'm not entirely sure of their sex. I think the Molly may be female but again I'm not positive. Also I've recently been dealing with an ammonia spike (NTS) which is why the Molly is slightly burnt. They seem to be doing better since I've been taking the necessary steps to improve the water. Currently have it down from 2 ppm to 0.25 ppm. But yeah.... What's with the chasing?