Wrasse help

[Coralgurl]

It appears my scotts wrasse has no scales on the front half of his body on one side. He doesn't come out unless to feed and it looks like he hides in the rocks, not the sand. I tried to get a pic but from the time I noticed to the time I got my camera, he's gone back into hiding.

It's like it's scales have just come off, there's a small bit that's still hanging on. He was out yesterday and I didn't see this then. What's going on?