Betta seeing his own reflection

Question
Hi,
I have recently moved my betta tank into a better location, and I took the time to clean the slime off the glass so the tank is nice and clean. However He can see his reflection on the bottom of the tank, and on the side of the tank. I put a white towel under the tank to stop him seeing his reflection there, however he is still flaring at himself on the glass. He sometimes gives it a little bud with his head and I am worried that he might kill himself doing it. He had done it before (about a week ago) in the old spot as the suns angle made a reflection visible. The stress caused fin rot as he was healing from it.

He is stressing out and I am worried it may cause another rot outbreak, or even death, either won't be good.

I heard that after a few days or so, this will pass? I can make the room completely dark which stops reflections at night, however it can't be a long term solution.

Any ideas?

Thanks,

Alex

Answer
Alexander,
Stress does not cause fin rot. Bad water quality causes fin rot. There should be gravel at the bottom of his tank it should not be bare. Since it is, he will see his reflection and will flare. You need to put 1 to 2 inches of gravel at the bottom of his tank. He will eventually stop flaring after you put the gravel in.