Do not feed them food that have been in the tank a few hours. The number of bacterial in the tank is large, after a few hours the bacterial count on the a piece of fish is incredible. In fact I would consider these food spoiled if they are not eaten in 1/2 hr. I have fed leftover clams to my Magnifica and kill him. Thinking about it afterward, I know this was the cause of my anemone's death. Hind sight is 20/20.