Woke up to see a white spot on gill.

As the title says I woke up this morning to see a strange white spot on one of my axolotls gills. I dont know if its debris or something else and I dont know what to do to try and brush it off if I can. He's acting fine, no weird gill movements or anything like that that. I tried to take a photo of it.

I went ahead and did a water quality check and these are my readings:

Ammonia: It looks between the 0 and .25 mark. I did a test on some regular non tank water and it looks the same so I think my test kit might be a little off on color.
Nitrite: 0
Nitrate: 5
PH: 7.4
Temp: 64 degrees

I tried to take a cotton swab and gently rub it off and it didnt budge and I didnt want to agitate him. I dont know if he somehow managed to get a bit of fungus on gills from something or if its a build up of slime coat (probably unlikly).

It doesnt help that our AC went out and the outside of my tank is completely covered in condensation, but I dont see it anywhere other than that one spot.

It's been 24 hours and the spot is looking the same. I am sure its a fungus though since from the back it looks cottony. My little guy ate like normal and is still just as plump and active as ever.

After doing a lot of research I know its not the temp or water quality so I am thinking he may have nicked it on something or his tank mate might have given him an, 'I need personal space' nip since she will sometimes do that if he tries to push past her.

I have read mixed things about salt baths. He's only about 3ish months old so I dont know if I would need to cut the salt in half if I give him one.

I have read that if the water quality and temp arent an issue it might just be a fluke thing because of a small cut or nip to leave it be for a week and monitor it to see if it heals itself as long as it doesnt get worse.

I have also read that instead of a salt bath a milder option is to let them soak for the same amount in some regular chlorinated tap water.

Im not sure which is the best option since I dont want to cause more stress.

I may not be much help or may not be correct here (I'm still fairly new) but when my guys were a little smaller I saw a very similar thing on their gills and tried to brush it off without any success but it went away after a couple days, I say you should maybe do more frequent water changes and keep the water cool and see if it gets any better, if not then it might be time for more drastic methods but with such a little guy I don't think you want to fridge or anything too quickly, they recover on their own pretty well

You could try the mildly antifungal effects of Indian almond leaves.

I've been keeping an eye on it and it seems to be going away. The clump that was there is gone and there is only a small trace left on the back of his gill. Im still keeping an eye on it but things are looking good. Fingers crossed!

That's great! I see you're from Florida too (are you having a hard time keeping the temp down too?) but tell us when all is good and everyone's healthy!