I bought a 30 gal tank with Mollies, tetras, cory cats and a pleco. The tank had been up and running for four years and we left a few inches of water in during transport so that the bacteria would not die off. Now 8 days later the silver molly is head-butting the black molly and chasing him around the tank ramming him in the side. The water is also a little cloudy today for the first time. The mollies both appear to be females. The male dalmation molly and other fish are acting normally. What could be wrong?