My betta can't calm down. I assume he can see his reflection in glass. He is frantically swimming back and fourth against the glass. He is so stressed I cannot feed him in the tank. He seems to be breathing very heavily. I've tried covering the sides of the tank with paper and cardboard, different light settings, and lining the edges of the tank with plants. I have tested the water, he has a heater and a filter in his own ten gallon. Any ideas on how to calm him or what else could possibly be wrong?