Possible fungus not responding to antifungal

Hi all,

I was hoping to get some advice on the next plan of attack for my situation. So, I have a common mudpuppy (Necturus maculosus) for almost a year now. And about 2 days I noticed what appeared to be some type of fungus growing on my mudpuppy's head (see picture). From online research I came to the conclusion that it was a fungus. I immediately cleaned out his entire tank and purified everything. I have placed him in a quarantine tank for the time being until I see some progress in the fungus getting better. To treat the fungus, I read on several forums, two methods of treatment: antifungal medicine for fish or salt baths. I bought a antifungal for fish whose active ingredient is Acriflavine and it's dye is Victoria Green. From what I read from these forums, that this is an acceptable form of treatment for him. I had placed him in an initial bath of it for 10 minutes because I know not to leave him in that solution for too long. I returned him to his hospital tank in hopes the fungus would start reducing. Instead, the fungus is spreading when I looked the next day (see picture). I repeated the 10 minute bath again yesterday as I hoped the medicine might take more time. But, today I just looked and it spread again. I am concerned and wondering what would be the proper step of treatment? Should I start a salt bath? If so, could someone explain how to make one and for how long should he be in it. I have never made one before.

Also, I got really concerned for him the evening of the day I removed him from the tank on the first day, he built up a lot of slime or possibly the fungus on his gills. But, the next day it seemed that went all away. Although when I handled him to move him to the bath, I noticed some of his gills fell off in my hand. That was really scary! Anyone has any thoughts or experience with that?

UPDATE: Okay, I just found the sticky thread of how to make a salt bath. So, I think I have that covered. Just would still like to hear other people's opinions on this matter. Thanks.

Fungal infections like this are likely a secondary issue, brought on by other health issues which lower the immune systems of the animal. The opportunistic fungi can then take advantage of wounds or other infections. I wish you the best with your friend.

UPDATE: I haven't really heard any suggestions on what I could do so, I just performed my first salt bath for him. I followed the steps on the thread about salt bath picture tutorial and left him in there for 12 minutes. I still would like some advice on this matter if anyone has any.

The one thing I could not find was how often to perform these salt baths? I saw one thread that said once a day and another that said 3 times a day? Thoughts?

Also, the "fungus" is even more aggressive than before and has now spread to his left eye.