When my dad was stationed at Roosevelt Roads, the Caribbean was the back yard. There were tiger sharks and lemon sharks around, but I was always more worried about barracudas. They eerily stalk and hover around around you. Creepy bastards.
Yeah, I was at Dry Tortugas a few years back, and I surfaced and chatted with a guy on the rampart. From up there, he coukd see into the water. He said, "just so you know, there's a giant barracuda that'd been stalking you...he's right over there." But of course, he was hanging out just out of my sight.