I am having this problem in my 320g tank with a 8" Jardini, 5" tiger dat and 2 10" motoro rays. I have blocked up the tank from light (using black garbage bags) but I am still feeding them 3 times a day (after partially letting the light in for a few minutes). As the fish are still young, would not feeding them for a few days stunt their growth? Especially the rays, they eat like pigs!
