Sorry I didn't mention in details. Ok here it goes:
I feed all my fish everyday. Frozen food, flakes and pellets. My yellow tang loves them all and gobble everything down during each feeding.
Other than those foods I also left him a 3"x3" sheet to chew every 3 times a week. But I have got another problem. Everytime I took the veggie clip out, my other fishes already know what I am up to and waiting for the nori too. Especially the bannerfish will start tearing things up, seems like he is eating it but sometimes he is just simply tear them apart. My yellow tang also takes bites on the nori too. This will only last max an hour or two before the whole sheet of nori is gone.
So in this case is 3 times a week will be enough?