Hi there. I own a 29 gallon tank that has six tetras, a lyretail dalmation molly, and her baby molly that is living in a smaller tank. As far as I can tell, the water levels are good. Recently, I have noticed my big molly acting strange. In the late afternoon, she will start to occasionally lean so far back that she is pointing straight up. She'll then vibrate rapidly before going back to normal. At times, a few tetras will even nip at her belly. Why might my molly be doing this and what can I do to help? On another note, would it be okay to add two more female mollies? In the past, big molly has been aggressive and caused the death of two other molly tank mates. I'm worried that she'll attack the newcomers or even vice versa, one or two of the newcomers will attack the others Please give advice. Thanks!