I looked for this in unhealthy fish....
Hmm, when koi are shaved (an archaic way of dealing with aggressive cases black fungus), they look like a shaved shi tzu in skin texture. Dry and almost velvety. And usually mostly a white color with tans or grey where the markings were.
Whemn the scales gre back you'd see shiny spots that looked like fingernail clippings (shiny hard half moons) , then pearls of scale, then a real scale and they would slowly fill the gap. A very slight cover of slime if you were rough or the water was not dead on. Nothing thick or fuzzy would have been considered healing though. I do not like the big fuzzies on tropicals while they heal. The make me really jumpy and itchiny fingered around the med cabinent!
Raw chicken(pinkish) is the sign of the skin being broken to expose true flesh and has a big chance of bacteria and fungus getting to close and friendly! Be sure you keep those salts up to gold capacity.... and again..lotsa water changes...
"Fish! Thank You! Oh, tropical huh? Did you buy a heater? Auuugh!"
Mega-pet stores prolly should not be allowed to sell animals as retail "items".