"Hold my hand," says Father, "or you're gonna go in the water and the tarpon's gonna eat you."
Nearby, a man in his 20s offers equally valuable advice to his pale-faced girlfriend.
"Heck, just hold the bait fish out and close your eyes."
In the green waters just off the dock, the tarpon soar. They're beautiful - dragons, shaped like torpedoes, rising from the water with a flash of silver, then falling back, unblinking, with the requisite baitfish and occasionally a piece of knuckle.
During the hour we spend at Robbie's, a steady stream of bucket-toting tourists plod out to the dock. This is Keys entrepreneurship at its finest.
"Definitely not a chain," says Chris, as we pull away.
Another great thing about eating in the Keys is - how to phrase this in proper epicurean terms - the food is cheap. If three dollars for a bowl of conch chowder is too pricey, well, 25 cents will buy you a coconut at a roadside stand. Like us, you can down mermaid's popcorn (deep-fried popcorn shrimp) and crack conch sandwiches on any number of listing wood decks, then dine on clams caribe (angel-hair pasta liberally doused with little necks in a red broth with island spices) at Kelly's Caribbean Bar/Grill & Brewery.
Kelly's is in Key West, which, along with several fistfuls of first-rate restaurants, is also home to the famed Mallory Square.
This is where I find myself on our final night, and as I take in a sunset, accompanied by the square's barking sword swallowers, chained Houdinis, fire jugglers, and an uncanny number of sixty-something men in shorts and black socks, I realize that I could be sad at the thought of returning home - but I'm not, because now, on my return trip, I know where to stop for a fish sandwich, blackened just so, topped with a Havana Red Ale and an ocean breeze.