After receiving a mandatory fishing license the crew head out to the middle of the Atlantic Ocean.
The entire scene of the crew fishing is hilarious. But my favourite part is when Bender after exchanging packages with an unknown person in a speedboat saying "Hey! Guess what you're accessories to?" The ship is pulled to the bottom of the Ocean by a colossal sized fish where Fry discovers the Lost City of Atlanta and it is inhabited by mermaids/mermen.
During this episode we see another of Fry's short lived romances. Discovering that a relationship with a mermaid would just never work. Over all an excellent episode.