Well there are several choices you can take. A divider in your tank to separate him from the other fish. Find what fish will be more agreeable with your molly and put in more plants for hiding. Give you molly away. Trade your molly in for another fish if the store will do that. I think you know the last chose.
Good luck,
Theresa

thank you so mush I eill tread it

Mollies are known to be killers. Be extremelly careful of what happens in the tank when you are not watching.