A white fluffy spot appeared on my black molly's right fin 3 days ago so i isolated it in a tank with some aquarium salt (roughly 1 tablespoon per 5 gallons). All seemed to be good and today morning i noticed that the white spot on the right fin has disappeared completely. I thought I'd leave the fish in the tank until tomorrow before slowly transferring it back to the main tank.
However, when I checked the fish again this evening, another white spot has started developing but this time, it was on the side of the fish's mouth
The fish has also gotten noticeably tired and sits at the bottom of the tank. It did not do that in the first 3 days. I tested the tank's water parameters and ammonia is 0, pH is about 7.9.
Should I continue to leave the fish in the tank and wait for the 2nd spot to heal or is there another method that would be more helpful in treating this condition? Any advice is appreciated!