Does my cory have a skin condition?

[Primordialsoup]

Hi guys! This morning I noticed that one of my 8 corys has a whitish area on the upper part of his tailfin that I don't think was there before. I can't exactly tell if it's fuzzy looking like fungus or some sort of skin condition but I'll post a picture. Does anybody know what this is on his tail and is it something that needs treatment? He's otherwise acting completely normally (as you can see he's eating a sinking wafer) and as far as I can tell none of the other corys seem to have this. It does appear to be on both sides of the fin.