He came much closer and I was able to see the black though I wasn't able to snap a pic. I also double, double checked it with my Humann books.
Tracey, I'd have to agree with Johnny, there are only two species of sharks in florida waters with that perticular profile, the bull shark and the sandbar (both having a large dorsal fin that starts even with the insertion of the pectoral fin). The blacktip's dorsal starts posterior to the pectoral fin. Black tips are not uncommon on younger bull sharks. The defining characteristic of the sandbar is an interdorsal ridge between the first and second dorsal fins which you could only tell by a physical exam.