Just wondering how you could buy it and not know what it is.
I don't quite understand what you mean by that. Are you saying that my not knowing the scientific name means I don't know anything about it? This may be news to you but LFS's mislabel things all the time. I knew it wasn't exactly what they said it was, but I have a decent enough knowledge of fish to predict it's needs and particulars, snapper care and behavior is fairly uniform between species. And just knowing a name means nothing if you don't know what the care requirements are.
When buying something that is rare enough that it is hard to identify even in Burgess's Atlas this can be expected.
And no it is not a damsel. I'll take that to mean you think it's pretty.