We begin our episode with the Simpsons watching a Muppet movie from TheSeventies featuring none other than Troy [=McClure=] ([[RunningGag You may remember him from such episodes as "The Simpsons 138th Episode Spectacular" and "Lisa the Vegetarian"!]]). While Marge reminisces about how Troy used to be quite the heartthrob in the '70s, Homer brings up exactly why his career's in the gutter nowadays: Troy has a sexual fetish for fish, and there's tell of an urban legend that he may have expressed his sick desire for fish at a local aquarium.
Meanwhile, Troy himself gets pulled over for reckless driving. Troy needs corrective lenses to drive, but he hates wearing them, as they make him look like a nerd. The next day, he heads over to the Springfield DMV to take the vision test there. Selma's the one giving him the test, and she's clearly smitten with Troy. Troy cuts her a deal: pass him, and he takes her out for dinner. The date goes a little awkwardly, but the paparazzi hound Troy and Selma on their way out of the restaurant. Seeing an opportunity to boost his image a little, Troy gives Selma a kiss on the cheek, and their date makes the tabloids. Troy's agent, [=MacArthur=] Parker calls him up to tell him to keep dating human women, as it would do wonders for his career. Selma gets a call from Troy asking her for another date.
The relationship seems to be going great, with Troy even proposing to Selma. His career's doing great, too, with Troy landing in a big-budget musical version of ''PlanetOfTheApes''. The night before the wedding, however, a drunk Troy confides to Homer that the marriage is a sham to help revive his career and get people to forget about his fetish...a detail that Homer only confides to Marge well after the ceremony.
Meanwhile, Parker tells Troy that he's being offered the role of [=McBain=]'s sidekick in, well, the upcoming [=McBain=] movie. With this opportunity in his sights, the sham has to continue. Marge and Patty, however, break the bad news to Selma, who doesn't believe it. When she gets home, though, she directly asks Troy if their marriage is fake. Troy eagerly admits that it is, but he convinces her that the marriage won't be so bad. So things keep running smoothly for the happy-ish couple, until Parker convinces Troy that, to truly land the [=McBain=] role, he has to have a kid. Selma begrudgingly agrees, but after one awkward, botched attempt (not helped by the fact that Troy apparently knows nothing about human sex), she calls the marriage off, saying that she can't bring a child into a loveless family. Selma walks back to her apartment with her iguana, Jub-Jub, and Troy eventually turns down the [=McBain=] film role...only to make his own risky vanity project, ''The Contrapulous Fabtraction of Professor Horatio Hufnagel''.
!!"A Fish Called Selma" contains examples of:
* BabiesMakeEverythingBetter: Deconstructed -- Troy's agent wants Troy and Selma to have a baby, but Troy doesn't know the first thing about sex with a real woman and Selma doesn't want to bring a child into a sham marriage.
* TheBeard: Selma, for Troy.
* BitingTheHandHumor: The final line reveals 20th Century Fox is willing to produce Troy's ridiculously outdated-sounding (it appears to be a throwback to 1960s family musicals) vanity project.
--> Selma: Is this a sham marriage!?
--> Troy: Sure, baby. Is that a problem?
* ByTheLightsOfTheirEyes: "Marge, could you close your eyes? I'm trying to sleep."
* CareerResurrection: Troy undergoes one after marrying Selma.
* CharacterDevelopment: The entire point of the episode was to provide this for Troy.
* EarthAllAlong: A line from ''[[PlanetOfTheApes Stop the Planet of the Apes, I Want to Get Off]]'' is the TropeNamer.
* EveryoneHasStandards: Selma may be a jerk to her brother-in-law, Homer, on many occasions and not seem to mind that she's being used to help Troy [=McClure=]'s career, but she refuses to have a baby with him, as she feels bringing a child into a sham marriage will negatively affect the kid.
* TheFantasticTropeOfWonderousTitles: ''The Contrapulous Fabtraction of Professor Horatio Hufnagel'' currently provides this trope's page image.
-->'''Parker:''' Paramount wants you to star in a buddy comedy with Rob Lowe and Hugh Grant.
-->'''Troy:''' Those ''sick '''freaks?!'''''
* ImGoingToDisneyWorld: Troy's reaction to the possibility of being [=McBain=]'s sidekick:
-->''Hot damn! I'm going to Sea World!''
* INeedAFreakingDrink: When Troy tries to have sex with Selma to conceive a child, he just keeps making roaring noise at the door of their bedroom. Selma wants to break the ice and offers him some wine. He quickly runs to the bed, empties both glasses, and returns to the door to continue with the roaring.
* InkSuitActor: JeffGoldblum as [=MacArthur=] Parker.
* PunnyName: [=MacArthur=] Parker is one on the song "[=MacArthur=] Park".
* RippedFromTheHeadlines: The premise of a celebrity marrying solely to convince the public that they have non-deviant sexual urges may have been inspired by the failed MichaelJackson-Lisa Marie Presley marriage, which ended a few months before this episode ran and was widely suspected of being a career-reviving ploy. (Columnist Jonah Goldberg actually referenced this episode in a ''National Review'' piece in 2005, as Jackson's child molestation trial was nearing its end.)
* ShoutOut: The musical ''Stop the Planet of the Apes, I Want to Get Off!'', in addition to being a parody of ''PlanetOfTheApes'', also contains the number "Dr. Zaius", set to a SuspiciouslySimilarSong to Falco's "Rock Me Amadeus". See also PunnyName above.
* SpeakNowOrForeverHoldYourPeace: Subverted; it looks like Homer might object, but he's too busy humming the tune to "Rock and Roll, Part 2" in his head.
* WeirdAside: How Homer lets the truth slip:
-->'''Marge:''' It was a beautiful wedding. I don't think I've seen Selma happier.
-->'''Homer:''' That reminds me — Troy said something interesting last night at the bar. Apparently he doesn't really love Selma and the marriage is just a sham to help his career. Well, enough talk. Let's snuggle.