Damn--NOT for fungus? That's what I was afraid of... I think maybe I need to do the entire week's treatment though? I hate starting something like this & not completing it, in case microbes get resistant.
If you do the combination I suggested you'll cover all the bases with no harm to the fish. I'll leave that up to you, there is nothing much else I can suggest.
The original affected fish has died. No surprise there... I started treating for parasite, with API Super Ick Cure. It won't hurt scaleless fish (I've got a BGK in there, among all the plecos) & doubled the salt (1tbsp/5g). I swear, the white spots (only on gill plates), are going away!