Betta fish and stress health effects

[DawnRiser9]

Mine was the same till I cut the light time to 6 hours. Now he's back to his feisty self. Maybe try a shorter photoperiod?

[luna4a]

Check the heater temp with a separate thermometer. Sometimes they malfunction and cook the fish. Had that happen once, scared me half to death.

[Vultaen]

Stress stripes are a dead giveaway. If you see vertical lines, something's definitely wrong. No stripes? Might just be a phase. Keep an eye on it.

[Cerulean]

Thanks for all the tips, everyone. Gonna try dimming the lights and adding some almond leaves. Appreciate the help!