You can feed dolphins, but that's all I'm aware of. You go to Rocky Point Preserve (look on the map) and there is a little hut that they sell fish at certain times of the day. The times will be posted on a sign. They only sell x amount of servings (to avoid over feeding) per time slot, and in the busy months the line is long before the actual opening of the hut. The dolphins are pretty active all day, and we don't even feed them. They're fun to watch either way.
You can "pet" sting rays without their stingers, star fish, and I can't remember anything else right now.
Have fun and show us your pics when you get back!