Need a helluva lot more info than that.
For a start, ammonia, nitrite, nitrate and pH readings, what size tank, how long has it been set up, how did you grow the filter bacteria? Have you added anything to the tank recently? What chemicals do you use?
How active is the fish?
How old is the fish?
How much is he eating?
How often do you feed him?
How long have these symptoms been apparent?