Coral beauty is not doing well

[Hud]

About a month ago bought a coral beauty and I bought it “quarantined”. But it stopped eating a couple days ago and it’s getting skinny. I have 2 clownfish with it that are doing great right now. It looks like it had lost its color and looks kind of dusty. I will post a video or picture of him down below. What is wrong with him. And what should I do? Thanks for a your help

 

[Hud]

Sorry I was cleaning my tank and I didn’t get a good picture

 

[DCR]

Dusty appearance often indicates velvet. If that is the case the treatment is typically copper in a quarantined tank, but it would need to be done very quickly to save him. Could also just be how the fish was collected or treated during the quarantine process.