I agree they'll probably be fine, but I think I'd go with a piece of black cloth to cover the tank and encourage them to settle down. Doesn't cost much and wouldn't be that much trouble. Even though my tank lights don't come on until mid afternoon, my fish get 'day active' as soon as light starts coming into the room. I would guess, and it's only a guess, that they'd do best with some sort of day/night cycle.