Redsea (Halfmoon) Damsel

[Ford_Prefect]

I recently, almost a month ago, baught this fish from work, the lfs. It started off all white with a darker hued fins. But a few days after i baught it, it turned brownish on the front half and white in the back. I thought maybe it was just from stress, but now, after another few weeks, its fading brown all over where the white part still was. plus it has like a neon type hue around the fins. The only thing i could possibly think of is maybe from the name "halfmoon" thought maybe it changed colors like phases of the moon. Anyone know for sure what it is? BTW asked someone@work and they said we dont get it in much and they didnt know too much about them.