My yellow tang hopped out of the tank. Found him on the ground. Don't know how long he was there. Put him back in the tank. He is alive and eating but has white spots over his eyes and seems to have trouble seeing. Hope he gets better. he is lucky. Question: If I put a glass lid on my tank to conserve water and keep fish in, will this prevent enough lite for the coral that I have *brain, trumpet, mushroom, feathery? Will the white spots go away on the eyes of my fish?