When the Planet Express company takes a fishing trip over the ocean, a colossal-mouth bass ends up dragging the entire ship under the sea. While the crew works on repairs to the ship, Fry falls in love with a beautiful blonde mermaid, and soon has to choose between leaving the Planet Express crew or staying with his new girlfriend in the (now undersea) city of Atlanta, Georgia.
- Arbitrary Skepticism: Fry points out how weird it is that despite having a crustacean alien as a coworker, no one believes that he saw a mermaid. Justified since in the future that Futurama takes place in aliens are commonplace while mermaids are still regarded as mythical.
- Artistic License Biology/Hollywood Evolution: When Bender points out that it would generally take millions of years for humans to evolve into merpeople, and questions how the people of Atlanta could've done so in less than a thousand, Umbriel explains that the leaking caffeine from the Coca-Cola plant had greatly sped up the evolution process.
- Artistic License Physics: The ship is pulled underwater and manages to withstand the pressure all the way to the bottom (they're specifically stated to be at "the exact center of the Atlantic Ocean"). There's a bit of a lampshade hanging here, since when the Professor is asked how many atmospheres of pressure the ship can withstand, he says (with some sarcasm) "Well, it's a spaceship, so anywhere between zero and one." (Futurama loves to play fast and loose with physics in general, so this isn't the worst example of bad science even in this episode.)
- Ass Shove: Professor Farnsworth presents Fry with an enormous egg-sized pill.
- And later in the same episode:Farnsworth: Before we go out, has everyone taken their pressure pill?
Amy: [annoyed look] Yes. Stop asking.
- And referenced later still, when the crew is introduced to a more efficient nose-plug-based method of breathing underwater:Farnsworth: This is uncomfortable and humiliating! Now, if they could put it in the form of a suppository...
- And referenced later still, when the crew is introduced to a more efficient nose-plug-based method of breathing underwater:
- And later in the same episode:
- Bait-and-Switch: When the crew comes across the sunken city and remove some of the seaweed from the name, the audience is being lead to believe that it's Atlantis. It turns out to be Atlanta.
- When this episode aired on Cartoon Network's Adult Swim block and TBS's "Too Funny to Sleep" block, the part where the Professor exclaims, "Sweet zombie Jesus!" after seeing the fish jump out of the water is edited. On Adult Swim, the line was "Sweet zombie [mute]" while on "Too Funny to Sleep," the entire line was cut. The line is uncensored on FOX (which normally cuts out any use of the word "Jesus" as an oath, since they did it to Seth MacFarlane's shows), the DVDs (original and rerelease), Netflix, Amazon Prime, Hulu, Comedy Central, and SyFy Channel.
- On Channel 4 in the UK, the part where Bender learns that the crew is on international watersnote and calls in a man to make an illicit deal (with Bender telling Fry and the Professor, "Hey, guess what you're accessories to.") was cut.
- Cassandra Truth: Nobody believes Fry saw a mermaid, chalking it up to Ocean Madness. Even when they find out he was telling the truth, they never apologize for disbelieving him.
- Cut His Heart Out with a Spoon: Hermes hates Nibbler so much he wants to put him in a sack, throw the sack into a river and hurl the river into space.
- Falling-in-Love Montage: Fry falls in love with a mermaid named Umbriel. They have a a montage set to "Atlantis" by Donovan. Fry and Umbriel ride a ray together, they watch a fight between an octopus and a small whale, and Fry makes a "I ♥ U" sign from bioluminescent creatures.
- Fanservice: Amy in a bikini in the first third of the episode.
- Fishing Episode: The episode begins with Hermes returning with a pet license for Nibbler, only he got a fishing license by mistake. A mandatory fishing license. So the Planet Express crew have to go fishing in the middle of the Atlantic Ocean.
- Fishing for Sole: Leela tries to use a harpoon to fish, but keeps getting boots. Even when she says she caught something twenty times heavier than a boot, she ended up catching a crate of ten pairs of boots.Amy: Oh, so this is where you shop for your boots.
- Giant Novelty Check: After catching the colossal-mouth bass, Prof. Farnsworth is given a giant check for breaking the world record for heaviest fish caught. Bender gladly pockets the check. Then Fry falls from the bass' mouth, dropping its weight below the record, and the mayor takes the check back, planning to give it to "some giant orphans."
- Giant Squid: Umbriel and Fry go to watch a fight between a giant squid and a sperm whale thats treated like a boxing match.
- I Choose to Stay: While the important people evacuated Atlanta, everyone else decided to remain behind on their porch swings and eventually evolve into mermaids "to sing, and dance, and ring in the new".Citizens: Hail, Atlanta!
- The Last of These Is Not Like the Others: Alongside the important celebrities that left the sinking Atlanta, there was someone known only as "The Magician". Leela questions why exactly he was important.
- The Last Straw: After Atlanta was relocated to the ocean, it began to sink due to overdevelopment—it was a statue of Ted Turner that put it over the top.
- Literalist Snarking: When the Planet Express gang goes fishing.Leela: I'm afraid you're both out of your league, boys, 'cause you're looking at a woman who owns her own harpoon!
Bender: Harpoon, my ass! (laughs)
Leela: Okay. (stabs Bender in the butt with her harpoon)
- Mermaid Problem: Fry ultimately leaves Umbriel to be with his friends after realizing that, as a human, he won't be able to have sex with her after she explains how sexual intercourse between merpeople works.Umbriel: I'm not your first, am I? I lay my eggs, and then I leave, then you release your fertilizer.
Fry: (racing to catch up with his friends) Why couldn't she have been the other kind of mermaid, with the fish part on top, and the lady part on the bottom?!
- My Friends... and Zoidberg: In the promotional video, Donovan explains that all the important people left Atlanta when it began to sink: "Ted Turner, Hank Aaron, Jeff Foxworthy, the man who invented Coca-Cola, the magician, and the other gods of our legends... and also Jane Fonda was there" (she and Ted Turner were married at the time the episode aired).
- No Party Like a Donner Party: With the Planet Express ship stuck underwater, Hermes quickly proposes cannibalism and suggests a lunch of lobster Zoidberg... I mean, lobster Newberg... I mean, Doctor Zoidberg.
- Not Helping Your Case: Umbriel tries to explain that Atlanta was more than just a hub for airplanes, showing off all the great sights the city had... topped off with the airport.
- Ocean Madness: The Trope Namer. Everyone believes that Fry has come down with this when he claims to have spotted a mermaid—be mindful that this is no excuse for ocean rudeness.
- Ow, My Body Part!: After Fry gets hit by Bender's fishing hook he yells "Ow, my small intestine!"
- Parody Assistance: Singer Donovan does a parody of his song "Atlantis".
- Pheromones: Professor Farnsworth uses a pheromone - a fish-attracting pheromone - to speed up fishing. He accidentally sprays some on himself, causing several marine animals, and Dr. Zoidberg the lobster-like alien, to become attracted to him.
- Putting the Pee in Pool: Occurs in two consecutive scenes. In the first, the mermaid swimming next to Fry remarks, "Did the water just get warmer?", and later, while next to a volcanic vent, she remarks, "Did the water just get cooler?".
- Rule of Funny: Zoidberg's house burns to the ground... underwater. Zoidberg wails "How could this have happened?" and Hermes notes, "That's a very good question." Implicitly claiming responsibility, Bender picks his still-lit cigar out of the ruins and puffs on it eliciting a cry of, "That just raises further questions!" What makes that really funny is that they explain everything that happens in that episode with pseudo-science, but for that one last thing, there's absolutely no scientific reasoning.
- Side Bet: Apparently Bender and Hermes had one about whether they'd find Fry alive or not.Bender: [seeing Fry with Umbriel] Fry! Oh I just knew you were still alive! [sotto voce] I owe you ten bucks, Hermes.
- Skewed Priorities: When the whole ship sinks into the ocean floor, Bender's only problem seems to be that the colossal-mouth bass he tried to catch with Amy's parasol got away.
- Status Quo Is God: Fry and Zoidberg almost stay in Atlanta, but are ultimately forced to return home after Fry runs into the Mermaid Problem and Zoidberg's underwater house burns down.
- Suntan Stencil: Bender takes Amy's parasol, resulting in her getting a sunburn. Bender assures her he put sunscreen on her back, but only enough to write "Honk if Bender is great".
- Super Not-Drowning Skills: Somehow, everyone who was on Atlanta when it sunk managed to survive underwater before eventually evolving into merpeople.
- Take That!: The episode takes multiple digs at Atlanta.
- Underwater City: Atlanti... er, Atlanta.
- Voodoo Shark: Played for Laughs when Zoidberg's home burns down... underwater. Also provides the current quote for the trope page.Zoidberg: My home! It burned down! How did this happen?
Hermes: That's a very good question.
Bender: [picks up a still smoldering cigar from the ashes] So that's where I left my cigar. (smokes the cigar)
Hermes: That just raises further questions!
- Water Is Air: See Rule of Funny and Voodoo Shark.
- Yank the Dog's Chain: Zoidberg gets an underwater home that he loves enough that he decides to stay in Atlanta... and then Bender (somehow) burns it down, forcing Zoidberg to return to the surface.
- You Have to Believe Me!: Fry can't convince the others that he saw a mermaid.