Carcharhinus melanopterus. I took this picture while on the Ocean Hunter III live-on-board in Palau. The cook used to discard leftover chicken from lunch into the ocean right behind the boat. This attracted blacktip reef sharks, and when caaaarefuly sliding into the water, they would swim with you for a few minutes, just enough time for 3 or 4 pictures, before they had enough of the human inbetween them and took off. Note the sharksucker on the underside of the shark. www.fishbase.org/summary/speciessummary.php?id=877