fish chasing

Question
Hi there,
        wondering if you can help? i recently got a new orange platy, and i have put it in my tank, and my black molly keeps chasing the platy, i don't think he is hurting he/she. but i am a bit concerned can you help?

Answer
Hi Kerry,
This is likely related to a breeding drive. Mollies, like many livebearers have a very high "mating" drive and they often will chase fish even of other species. It's really not harmful in most cases, however it can be stressful to the fish getting chased so just keep a close eye on the platy.

Sometimes the problem can solved if you keep only females together or have double the amount of female mollies to males.

I hope this helps!
Karen~