Is this neon tetra disease?

[Pisces_Girl01]

I tried to get more pics but he was terrified at being moved into the tiny cup so kept erratically moving.
I originally thought it was cotton mouth disease... thats still what it looks like to me actually.
I currently have him quarantining in a 4 gallon, water parameters are good, zero ammonia and nitrites, 5ppm nitrates, ph is 7.5-8ppm

I treated him with aquarium salt for 1 week and didnt see an improvement so moved on to meth blue. I started the meth nlue slowly as neons are so fragile... 4 drops initially and I just moved up to 7 drops today.
I haven't seen any improvement but he is still eating at least.
Any one have any ideas?

 

[Autumnsky]

Generally Neons are pretty delicate. And the amount of handling they can go through coming from the wholesalers, and how many times the stores employees try to scoop/ net fish, it is likely they could get a pinch or damage in scooping, and have an injury.

The extra stress just drives them into illness.

Making sure you have ideal and clean water, very low ammonia, 0 NitrIte and lower Nitrates in the safe range will be a first line of defense. That wat the fish body can work on healing instead of overcoming dangerous water quality issues.

Keep up water changes daily to give the best possible water.

The info in the diseases article below, might be able to help you.

This doesn't seem to be NTD, so far. I can't see the pic very clearly. It could be an injury which is getting some fungus which is more fluffy or a couple other diseases. NTD would be like a bump (is that what it looks like? Any other bumps or bulges on the body)

Getting a real or fake plant or adding some dark paper or a chunk of black trash bag on the back and sides to give the fish some cover and keeping the light level low or off. Those things also help give the fish some comfort. It is a shoaling fish so it will continue to feel somewhat stressed just because it doesn't have friends around it.

https://www.aquariumadvice.com/fish-disease-index-for-diagnosis-and-treatment/