I have a LED light thing attached to the top of my tank. I usually keep it on at night only because I think it's pretty, and I usually turn it off when I go to work and my boyfriend turns it on when he gets home. Should I leave it on? Or should I leave it off? Thanks!
My fish notice the changing of seasons during extended daylight hours or diminished daylight hours. They get sluggish much earlier in the fall and wake up earlier in the summer.
Just to keep it simple, turn it on and off during appropriate daytime/nighttime hours, not because it "looks pretty" :P. If you like the way it looks then look into getting a blue LED for a moonlight setting. I turn my lights on when I wake up and turn them off before I go to bed.