Something to consider is remove the fish put them in another tank. Totally empty the tank may want to add Potassium Permanganate. Squirt it out and start over, remove fish with net from hos tank back into new tank.
Fungal spores will circulate regardless of your actions. Unless the fish has broken its skin by injuring itself, I do not see the point of freaking out and then stripping everything down because of a mere fungus setting on the wood. If you are worried, remove the wood and disinfect it but it will eventually go away on its own.