The other day, at one of the two Petco's I can manage to get to, I did in fact find this rarity color.
I however, did not grab him
He was pink with a darker body coloring, and was a Half Moon to boot!
I was freaking out, because the place restocked. I walked out with my first crowntail that has green pigments in his translucent fins (another rarity), a half moon that is white with yellow accenting, and a half moon that has "big ears", dark blue with white edges on the fins (I guess a butterfly?). I dropped my 25% off a fish coupon and a $5 reward bucks on the counter and essentially got the crowntail at a steal!
Too many good bettas at Petco.