Apologies for the lousey photo but that's perhaps why I'm drawing such a blank on identifying this wee beastie. I can't recall the size but surely even with the features so out of focus this looks like it has to be a pretty easy ID .... but I can find nothing in the guides or on-line. The closest I can come is a transitioning initial to terminal phase Clown Wrasse (Halichoeres maculipinna) - this was actually suggested by an acquaintance on another forum but neither of us can come up with any clinching identification.
Help would be much appreciated - I'm pretty new to this but (as a life-long birder) this new world is really very exciting! And the fact that I might (even with my all too infrequent snorkelling trips) manage to actually help with field surveys is a real bonus.
All the best,