Sick Dwarf Gouramie - No QT
I have a sick dwarf gouramie. He was likely sick when I bought him a little less than 2 weeks ago. I went through great lengths to pick out the healthiest fish in the tank. Unfortunately, the guy netting him lost him and though I tried my best to follow him, I clearly failed. When I got home, I knew right away that it wasn't the fish I had picked. This one had a couple of small white spots on him. Anyway, the white spots have grown rather large and look like cottony fuzz which a little of comes off from time to time and floats around in the water. I'm guessing he has some sort of fungus or something?
Problem is, I don't have a QT tank, or anything suitable to move him into. There are 9 neon tetras in the tank with him. What do I do? Is there something I can use to treat the whole tank? Is he pretty much a goner, or is this generally treatable? I should mention that this is a fairly heavily planted tank, so if I can treat the whole tank, it has to be with something that is safe for plants. Also, I'm somewhat limited around here with what sorts of meds I can find, so multiple suggestions will be appreciated where possible. I'm guessing I don't have time to wait to order something online.
Thanks in advance for all your help.