Thanks for all the help. He is at a LFS I work at. He came in one of our Hawaii orders about a week ago. we feed frozen 2-3 times per week, otherwise flake/pellet. Nori soaked in garlic guard once a week. This guy grazes all day on algae in the tank. We have live rock and yes, fake plants/coral in the tanks. He eats a good amount for his size, still not sure why he is continuing to be this skinny. Some fish just slow down on feeding or stop completely. He is doing better though. We try to feed as much as possible but with 7,500 gallons of FOWLR/reef tanks and a 1,500g clownfish system, feeding 5+ times a day would be very time consuming on top of regular maintenance so we feed all at once Was just curious to see if anybody knew what type of tang this was. I agree with the Half Black Mimic