If you're out in the gulf, look for a passing mat of sargassum weed. All sorts of critters hang out underneath the sargassum as it floats with the current. Crabs, snails, fish, you name it. Last time I was over in Sanibel Island, I was surrounded by a school of tiny planehead filefish. These little buggers have the perfect coloration to blend in to the weed. They just swim along as the sargassum floats. Sargassumfish can also be found under the weed clumps (what a surprise...) but they are either less common, or more difficult to spot...or both. Also, there are times when you can't step three feet in any direction in the surf without finding a sand dollar with your toes. These echinoderms, as I'm sure you already know, are close relatives of sea urchins, but the spines are practically nonexistent. Just please don't pick these guys up out of the water...if you want to look at them, keep them just below the surface. They won't be as stressed out if they're not exposed to air. Happy snorkeling!