OK, thanks for all of the input. I will treat with the TS, I have no aquarium salt unfortunately, but if it doesn't clear up I'll make another trip to the pet store and pick up the things you recommended.
I bought a tank yesterday and took some fish with it. There was one male guppy in a 55 gallon with a bunch of albino cory cats and some platy. He isn't acting abnormally, and his fins look really good, but he's white towards his head. Pictures are linked.
Guppy