Thanks Sam, you're right - I posted the wrong fish (stress).
It was an Angel like in the photo. I thought today "it was on its way out when I brought it home - it went thin awfully fast..." but then realized I was merely deflecting the blame and the responsiblity - the fish was fine in the store - that's what attracted me to it. I didn't read enough to know how very shy these are, and how inappropriate it was for my tank, with a torpedo Tang and a Purple being added almost simultaneously.
On a brighter note, the Purple
Tang came home last Sunday from Edmonton (thanks again to Will the Driver). It has almost made peace with my Blonde Naso and is a welcome (and healthy) addition. I think this 100gal is maxed out now: Naso, Purple, Lemonpeel Angel, YTdamsel, and a small Mandarin.
Until my next impulse purchase - SMACK!