Well, it is certainly a female wrasse of the Halichoeres genus. That's the easy part. The hard part is what species...
Someone will surely jump in here and say "Halichoeres melanurus"; I can am certain it is not. Here's why: a distinguishing feature of melanurus is a single line which enters the eye at its anterior, then bifurcates at the eyes posterior. You can clearly see the line before the eye is in fact, two distinct lines.
What it does most closely resembles to me is Halichoeres richmondi, However I also see a chance it could be Halichoeres kallochroma, but I suspect richmondi is likely correct. A picture with better clarity of the tail might make that distinction.