Orange Shoulder Tang - Marking or colour transition?

[figwig]

Hey all. Noticed this mark on my OST's right hand side today, it's bigger than most marks I've seen as diseases so was wondering if it was something to be concerned about or if it's a sting from my foxface or the beginning of the colour transition? Thanks

 

[Roachbeef19]

Transition!!!!!!

 

[Jamesmost]

Transition,,, cool to watch.....

 

[DaneGer21]

Wait until the yellow fades!

 

[Jay Hemdal]

The dusky coloration on the belly is something else though - probably just superficial, but def. not normal.

Jay

 

[figwig]

The dusky coloration is what I'm asking after, I know the orange stripe is the beginning of transition but was slightly worried about the darker patch. I've circled it here

 

[Roachbeef19]

Got one coming in about two weeks with 5 other tangs!!!!! All in qt right now