Sometimes flukes look like a lifted scale. If you can look really close and the fish sits still you may be able to see them move. If not, see if they are in one spot one day and another the next. Flukes can make fish scratch also. If you think it's flukes and can catch him, do a 5 min freshwater dip. Flukes turn cloudy white in FW and fall off. They look like the scales falling off the fish.,This eliminates the flukes from the fish but not the rest of them in the tank. Hope it's not flukes.