My ornante is kind of like that. He is more reclusive so the dels usually grab the food before he can get to it right away. So I usually try to feed that tank twice a day with once during lights on and once during lights off and also try to make sure I spread the food on both sides of the tank. Even though I don't see him eat much he must be because he's not losing any weight. So try spreading it about a couple times a day both with lights on & off and see how he does.