Illness/Sickness: Please Help

[Spreen]

Our axolotl Marshmallow has been having some issues. This is our second axolotl. The previous one never had any issues but sadly we had to give him up due to moving around constantly. Marshmallow here looks as though she has some kind of fungus going on. In the photos you can see some of her gills have been totally eaten away.

She is on her own in a 55 gallon tank. The substrate is fine black aquarium sand. There are various plants (anubias, java ferns, Moss balls, etc). She had a few ghost shrimp present to give her some food since we left for vacation. They have since been removed as a possible cause of stress or irritant.

We had someone coming to feed here every other day (earthworms). Upon coming back home here nitrates skyrocket to 80ppm, when they were below 10 to 20 when we left. We did almost an 80percent water change. Readings are now 0.25ppm ammonia, 0ppm nitrite, and 5ppm nitrate. Her tank temperature is usually around 62to65 F. We have a cannister filter that creates little to no flow which shouldn't be irritating her.

What is my next step that I should take? I've heard about salt baths, tea baths, fridging, etc. I'm not sure what I should do for her.

Thanks in advance for any suggestions!

 

[Spreen]

For comparison this is how her gills look around 2 to 3 months ago when we got her.

 

[Hayleyy]

It does look like there is a bit of fungus on the gills. I usually use salt baths as they fix the issue really quickly. An alternative is tea baths, but I have found it is not as effective.
The gills shrinking is most likely a result of the water parameters. Once they are in check you should see the gills start to grow back like they were.
Until you can get the ammonia back down to 0ppm I would keep the axolotl in a tub with 100% daily water changes with dechlorinated water. This will let marshmallow start to heal, and your tank should cycle through faster. I you do tub the axie you can stop water changes so the ammonia can get eaten up. Treat it like a new cycle. Once you're getting good levels of nitrates you can start small water changes and at 0 ammonia/nitrites she will be okay to go back in to continue healing. Hope this helps!

 

[Spreen]

Thanks for the advice. We will work on getting the parameters back to normal and keep an eye on her. If it comes to it we will pursue the salt bath option.