Naso Tang not eating when fed...

[PEA]

Just got a Naso Tang about a week ago. It's a 135 gallon tank with two Clarkii Clowns and Sailfin Tang and Yellow Tang. I picked up the Sailfin and Yellow at the same time and the Sailfin can't eat enough. The Yellow eats some, but mostly likes to pick at the rocks. Tested the water and everything is spot on...

The problem is that the Naso won't eat anything that I try to feed it. It just swims right by. I've tried Mysis, Formula One and Two pellets, seaweed on a clip all soaked in garlic and it just swims right by. The only time I've seen him eat is if I stick some seaweed in my plate corals mouth and it will pull it from the plate corals mouth. Only thing it does eat is stuff it picks off the rocks. It seems acclimatized to the tank and is social to the other fishes. Just getting abit worried since it seems to be getting really skinny now.