Is it a new fish? I ordered one offline, had it in QT for about 2 months and never saw the thing eat a single piece of food. It just nipped at the rock all day long. Mine eventually showed nasty signs of a bacterial infection and didn't make it, hopefully you can get yours to eat. I tried everything: brine, mysis, blood worms, nori, pellets, flakes, LRS frenzy, etc. I also tried Kent Marine Garlic Extreme as well, didn't help, but in most cases it does.