Betta fish stressed out by light?

[Ellena]

Do betta fish get stressed out by bright lights? I have a mini heater in the water for my fish, and it emits a small but bright light. My fish becomes very active whenever it is on. At first I thought that it was happy with the warmer water, but then I realised that it might be stressed by it. Please help, thanks

 

[catx]

All heaters have some kind of light, it shouldn't be causing a great deal of stress at all. I would imagine the fish is either challenging this glowing intruder or just reacting to the little change in the environment. But I wouldn't be too concerned.