Is this Neon Tetra disease in my school of Cardinals?

I've had a school of cardinal tetras for 2+ years and the whole time I've had them there is a "white tumor/growth" disease always present. It never really looks fuzzy like a fungus... more like a white sore. It doesn't seem particularly lethal. I've seen affected fish in the tank for weeks. Maybe they die from it, maybe not. I never can tell. I probably lose a Cardinal a month or so (Is this normal?).

My water is good. 0/0/5 on A/N/N. The water is soft <100ppm, frequently changed, etc etc.

I have Apistogramma, Bolivan Rams, Ottos and Rummy nose Tetras and I don't see signs of the white sores on any of them - ever.

I'm attaching some pictures... I know they are pretty bad for diagnosis... Ever try to get Cardinal Tetras to sit still for a picture?

I'm just curious what this is disease is...

Is it normal Cardinal tumor part of life? Is it a disease (it doesn't kill them quickly if at all)? Do Cardinals kind of die from time to time? I buy 20 every 6 months... is that normal?

Any help or input would be appreciated. I love the species and I don't have a problem putting money into my school from time to time but I would like to know if my experience is normal with them or if they are sick.

Thanks in advance!

Thanks for the replies.

I had an Ich outbreak once but it didn't look anything like this. But this stuff does look more fungal than anything ... if anything.

The strangest part about this is, the fish don't really seem to care. I've seen fish swimming around for days or weeks with the white growths and they don't die or if they do, it's not a quick sickly death. I don't see them down, hiding, not eating, clamped fins like every other sick fish I've had before.

I've got four of the Cardinals in my quarantine tank right now. These were the ones I could see in the pictures which had the obvious white growths. After a few days, they don't seem to be getting worse... if anything maybe a little bit better.

I would think if it was NTD it would have certainly jumped to my Rummynose Tetras but I've never seen a single one of them looking ill.

I'm really confused.

So... almost a month later... one of the four (not the worst looking one) died the next day after I posted. The other three are still chillin in quarantine. I gave them two doses of Fungus Guard tablets and then a Paraguard tablet (after the water changes recommended).

No change. No death. Still the same white "patch" on the side of them. In the same order when I took them out of my main tank. 1 really bad. 1 slightly and 1 barely.

After 30 days should I return them to the herd or just say "you have to live your days in quarantine with your white patches?"

Is this really a disease or just some random Cardinal Tetra ailment?

Thoughts? Ideas?