Betta Flaring Up and Attacking Tank

[dwillis3008]

I have had my betta fish for about 2 years now and have never had a problem, but I decided today that I wanted to give him a housing upgrade. So I went to the store and bought and acrylic tank with a filter, air pump, and led lighting. The tank looks really nice, but when I put him in there and turned on the leds, he started flaring his gills like I've never seen before (super ugly btw), and biting and lunging at the side of the tank. Should I get a different tank? If it because it's acrylic and not glass? What can I do to fix this?

 

[Autumnsky]

He likely sees his reflection in the side. Maybe reduce the light a little. Can put some needle point mesh at the part where the light shines in. Or people use window screen to block part of the light. He will likely get used to it after awhile.

 

[Delapool]

Mine did that and settled down. Never did any damage. After that I think he spent most of time checking out his reflection.