HLLE? Black ich? What is on my yellow tang?

[cat_fish_lady]

So I have an issue I noticed with my yellow tang about 2-3 weeks ago, and since then I have SCOURED the internet/literature, even veterinary textbooks, and can't quite figure out what this is.

My yellow tang has small black spots that look as though they are enlarged pores (ie, not raised, and very small). But they are only around the head (which led me to think it might be head/lateral line erosion). However, every picture/description I have read of HLLE (admittedly common in this species) has said that fish generally have a LIGHTER coloration around the head/lateral line when they have HLLE. Same goes for "hole in the head" syndrome. So then I thought "black ich" (or other parasite), also common in the species. Yet I don't think this is black ich either because it is literally ONLY around his head in a very specific pattern resembling HLLE, and has been that way for weeks.

He is otherwise eating/behaving normally, though I did catch him flashing/scratching against rocks on the very first day he was moved from the old apartment, but have not seen him do this since then (that was about a month ago)

I took a billion pics of him but the black spots are just too small, they don't show up in any of them. I don't want to ignore a potential problem, but also don't want to stress the fish over nothing.

Has anyone heard of anything like this/seen pics of anything like this?

Tank parameters:
SG 1.025, Ammonia and Nitrites 0, Nitrates 10 ppm, Temperature 78 degrees, pH 8.2, Alk~ 10.0 dKH

[Cliff]

Does it look like the below ?

[cat_fish_lady]

Nope... actually if you want to see what the coloration looks like here are 2 pics of him, not incredibly helpful as the black spots don't even show up in the pic but at least it'll help rule out what diseases he DOESN'T have...

[cat_fish_lady]

*sigh* so it doesn't matter now I guess... came home this morning and tang was dead.

I don't know what happened... checked the levels again, all same as before. He was eating fine, had lots of nori strips and algae tabs available to him at all times and lots of algae on the rocks. Everyone left him alone. The only change made to the tank was the addition of new Koralia powerheads (2 x 1400 gph, so considerably more powerful than ones in there before), but I can't believe that that would cause it. And everything else in the tank looks great, including nems.

Well, I'm stumped. Guess I'll never find out.