Betta flaring at reflection in tank?

Sep 2, 2006
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I cycled my tank, moved, and brought home my first fish. I very attractive crown tail betta that I have named Shiggy, but my kids call Beautiful. I decided to use the 10 gallon tank as I was concerned about the swift current in the smaller tank with the filter that I am using.

Everything is going fine, but Shiggy is one aggressive little fish. He flares at his own reflection in the glass of the tank. One time he even charged so hard that he actually hit the glass. He does it constantly with the tank light on and the room lights off. With the room lights on, he only does it near the filter where I guess the black body causes the reflection to happen.

I understand that this could cause him stress. Is there anything I could do about it?