I'm amazed that you could even get near one of these to get this close a shot. It seems a touch over-enhanced perhaps. Hard to tell, flys have shiny abdomens anyway.
I really like the shadow of the fly. I think that really adds to this picture. But for some reason my eye keeps going to the point where all the veins of the leaves meet. It almost feels like the subject to me. Overall this is a great shot.
The point from where the veins of the leave radiate outwards seems to draw more attention than the fly. It is distracting if the fly is what you want to focus on. Also, lighting is particularly harsh, did you explore possibility of a diffuser?