White fuzzy patch

Water changes and monitor. I'd probably go so far as to set up a hospital tank and have it ready. If it doesn't improve or starts getting worse, pulling it for treatment will be easier that way.

I would watch for now...but will tell you what I swear by now....Voogle. I picked some up a while ago. I set up a betta for my son and of course the one he picked out looked like hell. It was seriously close to death and almost all his fins were gone. It took like 2 days before he had what looked like fungus. I started adding the voogle everyday...this fish got well so fast I couldn't believe it. Then a while later I bought some rainbows from...dare I say it....petsmart. One of them started almost immediately developing white fuzzy patches around it's gills. I had just planted the tank and really didn't want to do daily water changes. I went to the voogle again....it was amazing how quickly it disappeared. Now...could it be coincidental? maybe. But, it's not a med, not an antibiotic and did not harm my biofiltration or my plants.