I just transferred my new betta to a 5 gallon tank complete with hiding places, filter, and heater. He loves the extra space, but when I turn on the light (very bright fluorescent bulb) he swims around and around the tank flaring at his reflection. He only stops when I turn off the light. I know excessive flaring can cause stress which can weaken his immune system and shorten his life. Would it help if I got a dimmer bulb? I was thinking of getting a background and more plants to hide the back and side walls as well...