Absolute stumper: Sick flame wrasse

[cpage3]

Hey everyone,
I have a flame wrasse that is in bad shape. He has lost most of his ability to swim normally in the water. The fish appears fine other than the fact that the fish can't swim. His breathing is normal, his colors are vibrant but he can't use his tail and he cant stay bouyant in the water.

The fish would be absolutely fine if it werent for this problem it is even still eating things when it can reach it. Anyone, have any idea what is going on and how I can treat it?

Thank you,
Chris