in order to help, we're going to need a lot more information. would you call up your doctor and say, "hey doc, i'm not feeling well, what should i do?"
what size is the tank.
how many and what kind of fish are in it.
what are your ammonia, nitrite and nitrate readings.
how often do you change the water and how much do you change.
how often do you vacuum the gravel.
what are you feeding your fish.
how long has the fish exhibited these symptoms.
how long have you had the fish.