He'll kill her if you don't move them. Even if you do move them, there is a chance she won't survive. Your male sounds to be very aggressive. Put them in the larger tank with plenty of plants and caves to see what will happen. Gourami have a reputation for being aggressive, so for the fish who fit that description, this is normal behavior. Honey gourami are typically gentle, but gold gourami, such as the species you have, can be quite mean. They also get very large. I recently rehomed a male which was about six inches long. He came with a tank I purchased, otherwise I would have never had him.