My Maxspect Ethereal has a moonlight function but it is fairly dull and doesn't light the tank all that much, it's more like ambient lighting for the room really. Both of my clownfish go into their sleep-like trance thing that they do and hug their frogspawn all night so I don't think it bothers them, my melanurus wrasse buries himself so I know it doesn't bother him, my goby sleeps in its cave with the pistol shrimp, and my hawkfish sleeps in a little crevasse all night so it probably doesn't bother him either.