Orange Shoulder tang; disease, or natural change?

[michika]

My tank gets fed once daily, and I feed a huge variety of foods through the week. Nori is available constantly though.

Frozen:
-brine enriched with spirulina
-krill, she/it eats it, but its really for my sixline wrasse who goes crazy for it.
-mysis
-ocean plankton
-blood worms
-rotifers

Pellet/Flake
-Cyclopses
-Spirulina flakes
-New Life Spectrum
-Ocean Nutrition's Formula One

I also dose phyto (t.iso, and nano varieties) for my rather large clam population.

She/it eats really well, readily accepts just about anything, but doesn't really seem to like nori, as she prefers hair algae instead (no complaints!)