I noticed your post here. I too have a Naso that was not a real good eater at first. He is now a monster pig. Two suggestions:
- Romaine Lettuce - It has very little nutritional value.... but I found these fish go ape over it. As an enticement, pick up some romaine lettuce and clip it or band it to a rock.
- I don't feed nori from LFS or on-line. That *%$& is crazy expensive. I do feed my fish a dryed, non-salted, no preservative seaweed I get from a local grocery store. I get a package for $3-4 that pretty much lasts me an entire month. I cut the sheets down to about 3" squares which is about a 1/4 of the original size and I store them in a ziplock bag. I also feed one square a day, usually in the morning. My Naso, Yellow and Rabbit fish all munch it. But the Naso is the king.
- I also feed Rod's reef food along with Atlantic plankton and mysis.
The trick for me was to get him to eat and the romaine did it. I wouldn't feed it for too long as many will say here it has very little nutritional value. But...if it can help the fish to get to eat... great. By the way, I have heard that a lot of the collectors and distributors will also feed lettuce to their tangs when they are collected and transported.
I hope this helps!