How do I know when the fish is not contagious?

[ElvisMinnow]

I am rescuing a little guppy who had gotten a fuzzy fungus ball on his dorsal fin. He had been living in an isolated, poorly maintained bowl--NOT mine.

I knocked the fungus off with a Q-tip and put him in a container with an appropriate dash of API Fungus Cure and a few grains of API Aquarium Salt.
After a week of treatment with the Fungus Cure (as directed), there are no indications of external fungus and the fish looks pretty lively.

How long do I leave him isolated in this bowl? When is he "cured"?

Thanks, folks.

 

[jsoong]

I would wait 2 weeks at a minimum, in case something else shows up. Some would go 30 days, esp. if your main tank has valuable fish.