Some bettas won t eat at all when stressed by too much light.
Betta fish light at night.
You ll see this stress play out in feeding habits mostly.
Are you wondering whether you should leave your betta fish light on or off at night.
You should aim to give your betta 8 12 hours of light and 12 16 hours of dark per day.
The easiest way to do that is by turning the tank light on when you get up in the morning and switching it off when you go to bed at night.
If your betta fish has too much light it can become overly stimulated and stressed.
However just like their wild cousins captive betta fish do need to sleep at night.
Your betta has a day night cycle it follows just like you.
So you must turn out the tank lights overnight to replicate the natural day night cycle that the fish enjoy in the wild.