OK so I got an AWSOME new tank last night!!

It's a 2.5 gallon with a true aquarium light and a filter. My only problem is that if all of the lights are off, exept for the tank light, his reflection shows in the glass. He flares out his gills, but if thats the only light on, he'll keep doing it all the time. If I keep his light on & the room light on, whats the point of having a tank light? Does He just need time getting used to his tank?
Hmmm....
Please Help
THNKS
BTW I have it on Right Now But he's mostly Spazzing out!
Now hes flaring at me...