reefmaniac, what are you feeding?? From my experience, very few fish can refuse brine shrimp - live or frozen (enriched if possible) are fine. Whilst not overly nutritious, it generally gets them feeding and buys you some time to get them eating other prepared foods. Nori is also good, and should become a staple for your tang - hold it in the water for a minute and then rub it between your fingers to effectively shred it. I would be surprised if your YT did not eat this.
Good luck.
Good luck.