Hi:
quote"i dont know what is wrong"
an neither do we w/o more information.
Can you quickly run down your tank specs, water parameters(which i feel might be at fault here), tankmates, how long the fish has been iun the tank, your feeding regamin.
Fading colors can suggest anything from poor diet to poor water quality. Discolored scales may suggest something else. Do you notice anything going on w/ the fish? has he stopped feeding, or is acting strange
frank