Fishless for about 6-8 weeks. 8 I believe. Feed your inverts with pellets or any food that can reach/settle on the bottom or rocks. No need to clean the tank beyond the fishless thing. Those nasties can't live without fish hosts. All the established bacteria is something you wanna keep alive. No chlorine or other solution.
Can you get a decent pic of the infected fish?
So, gonna do a QT tanks next time???
Some never QT and NEVER have a problem. All it took was once for me long ago to change my ways.