Dave,
I came across this earlier today. Down at the bottom you will notice a section talking about treating fungus. I am NOT a frog specialist, but I do find that people on this forum are very helpful:
"Fungus on skin.
Red Leg, Pseudomonas, Hydrophila.
Use the water area of a quarantine vivarium and add 0.6% SALT by volume. Make sure that the frog gets in the water often. Duration 6 weeks (refresh water often). Use a solution of 0.2% MERBROMIN (MERCUROCHROME)on areas of the frog with fungus, rinse after several minutes. "