My Archie flares non- stop when the light in his 2 gallon hex is on.
I had to move Harvey from that same tank for that reason, but I thought he was just hyperactive. Now, Archie is doing it too - Harvey used to flare at all sides of the tank, Archie just does it at the bottom of the back - that's where I have a blue background taped to the tank. Dunno if that's related??
Anyhow - here's Archie in his new home: (I just got him 3 days ago now)
As you can see, he's flaring like crazy.
So, since Archie's in our living room, the lights are on in the living room during the evenings, and there's natural light that comes in thru the patio door, so the ONLY time I have his tank light on is for about 15 minutes in the evening, and ditto in the morning when I feed him so he can see the food.
Otherwise I'm afraid he'd have a heart attack. yikes.