I have 2 axolotls in a 20g long tank, a few days ago I noticed one had developed a large amount of of fungus. The other is completely clean/fine and remains in tank(after performing a large water change as a precaution). The affected has been isolated and was given a salt bath. I waited a day after the initial salt bath to see how she reacted, at this time I did not notice any redness, most fungus had disappeared. Today upon administering another salt bath I noticed large areas of redness and sores, there seems to be redness and a split in the tail. No live feeders have been used or any additional tankmates.
What is my best course of action?
What is my best course of action?