How much do you feed the fish, and how often? I used to overfeed and it caused lots of wierd problems. Now, I feed enough food that all the fish get a pellet or two, and some hits the bottom for the clown loaches. In 60 seconds, all the pellets are gone. Nothing left sitting on the bottom. I feed once a day, and I think that may be too much. A fish in the jungle can go a week without eating no problem. ETA: Just to give you an idea, I have 20 CA Cichlids range in size from 4-8 inches, and 5 2-3 inch Clown Loaches. I feed all those fish 3/4 teaspoon of NLS pellets--that might still be too much. I USED to feed more than that sometimes twice daily when there were 10 fish at 2 inches--that's overfeeding.
And don't turn on the lights at all for the next week. Only time I turn on my lights is when I want to look at the fish. Fish don't care if the lights are on or not. As long as they can tell, from ambient light from across the room, that it's daytime, they don't need any lights on at all. I don't think that's even necessary. Lights grow algae not fish, so why turn em on if you don't have plants in the tank?
ETA: Just to give you an idea, I have 20 CA Cichlids range in size from 4-8 inches, and 5 2-3 inch Clown Loaches. I feed all those fish 3/4 teaspoon of NLS pellets--that might still be too much. I USED to feed more than that sometimes twice daily when there were 10 fish at 2 inches--that's overfeeding. "Overfeeding" is very easy to do--you don't realize you're doing it until you make a real effort to think it through, set yourself a limit, maybe even measure it out.
