!! The Disney movie
* DevelopmentHell: Creator/WaltDisney himself commissioned an early storyboard that hedged much closer to the Andersen original, which the crew of the final version eventually discovered. You can see these sketches on the DVD.
* DuelingMovies: Released just a few days before ''WesternAnimation/AllDogsGoToHeaven'', and unlike the last [[Disney/TheGreatMouseDetective Walt]] [[Disney/OliverAndCompany Disney]] vs. [[WesternAnimation/AnAmericanTail Don]] [[WesternAnimation/TheLandBeforeTime Bluth]] matchups, the Disney film would be the most successful.
* ExecutiveMeddling: Jeffrey Katzenberg caused the animators and others working on the film quite a bit of grief. One memorable instance was his insistence that the whole "Part of Your World" sequence be excised from the film, saying that he found it "boring" and also because he saw a child drop a box of popcorn during that moment in a test screening. Animator Glen Keane eventually persuaded Katzenberg to let them test the film again with that scene intact, and the positive response convinced Katzenberg to leave it in.
* GeniusBonus: Ursula's incantation for casting the spell on Ariel includes the words "Laryngitis" and "Glossitis". Someone well-versed in medical terminology would notice that they are a rather common conditions that may result in mute-ness.
* HeyItsThatGuy: Prince Eric shares a voice with [[SpiderManTheAnimatedSeries yet another character who has a thing for redheads]].
** A BehindTheScenes example, but the actress who served as the reference model for Ariel? [[WesternAnimation/{{Animaniacs}} Slappy Squirrel]] (Sherri Stoner).
* HeyItsThatVoice: Ariel... or should that be [[WesternAnimation/ToyStory2 Barbie]]?
** Eric [[SpiderManTheAnimatedSeries sounds suspiciously like a certain wall-crawling hero...]]
*** In Spain, Eric is [[LazyTown Sportacus]].
** King Triton is a [[Film/TheProducers Nazi]] and [[WesternAnimation/TheLandBeforeTime Littlefoot's grandfather]].
** Ursula was once a gym instructor and the ''principal'' of a certain [[WesternAnimation/GalaxyHigh intergalactic high school]]...
** The Norwegian Ariel is played by Sissel Kyrkjebø, whose voice was so beautiful they decided to use her for the Swedish (dialogue and vocal) and Danish (vocal) version as well.
*** As of "Return to the Sea", Ariel is currently [[Disney/{{BeautyAndTheBeast}} Belle]] in the Danish dubbing. In Norway, she is [[Disney/{{Pocahontas}} Pocahontas]]. In Sweden, she is [[PhineasAndFerb Linda]], [[Disney/{{Hercules}} Meg]], and [[Disney/{{Aladdin}} Jasmine]].
** The Norwegian voice actors who played Ursula and Sebastian in the movie were married at the time (Frøydis Armand and Helge Jordal). They have one child.
** Grimsby is voiced by Ben Wright, the same gentleman who voiced Roger in ''Disney/OneHundredAndOneDalmatians''. According to the actor, when he showed up to audition, no one knew who he was.
** The Evil Manta from the series is voiced by Creator/TimCurry.
** Scuttle is Creator/BuddyHackett.
** Chef Louis is Rene Auberjonois ([[Series/{{Benson}} Clayton Endicott III]], [[Series/StarTrekDeepSpaceNine Odo]] and [[WesternAnimation/SuperFriends Desaad]]).
** In the Japanese dub, [[Creator/KazuhikoInoue Prince Eric]] and [[{{Kujira}} Ursula]] are [[Manga/{{Naruto}} Kakashi Hatake and Orochimaru]] respectively.
** Don't forget [[RicaMatsumoto Flounder]] and [[Anime/{{Pokemon}} Ash Ketchum]] too!
** In the sequel, Tip is voiced by [[Creator/MaxCasella Max Casella]] and Wataru Takagi in English and Japanese, respectively. Both also provided a voice in the [[{{Franchise/JakAndDaxter}} Jak and Daxter]] games; Daxter and Pecker, respectively. This is ironic, as both characters are enemies, and often fight with one another.
*** And don't forget that Undertow is [[{{Franchise/JakAndDaxter}} Baron Praxis]]; in this film, [[spoiler: he eats Daxter]]!
*** Also, [[Creator/TaraStrong Melody]] is [[Franchise/JakAndDaxter Keira, Seem]], [[Franchise/RatchetAndClank Talwyn]] and [[VideoGame/FinalFantasyX Rikku]].
** In Hungary and Italy, Melody is [[WesternAnimation/BobsBurgers Louise Belcher]].
** That little seahorse at the beginning is [[WesternAnimation/TheLandBeforeTime Petrie]].
** In Poland, Prince Eric and Ariel are [[WesternAnimation/ScoobyDoo Fred and Daphne]], Sebastian is [[Disney/TheLionKing Pumbaa]] and Triton is [[WesternAnimation/TheFlintstones Fred Flintston]] andJafar. Also, Melody is [[Disney/TheLionKing Kiara]], while Scuttle is [[Disney/WinnieThePooh Rabbit]], [[Disney/SleepingBeauty King Stefan]], Iago and Ludvig von Drake.
* HilariousInHindsight: In Triton's entrance, there's a cameo of Mickey, Donald and Goofy years before [[VideoGame/KingdomHearts the latter two go there themselves]]
* KeepCirculatingTheTapes: When it comes to the TV series, only about half of the series is available on VHS (plus three as part of the ''Disney Princess'' DVD line). The rest went unreleased.
* TheOtherDarrin: Flounder has been replaced various times during the franchise, due to being (most of the time) voiced by a real kid. Jason Marin played him in the first film. Edan Gross played him for the first half of the television series, and was replaced with Bradley Pierce. Courtland Mead voiced him for merchandise released in the `90s (including the Animated Storybook CD-ROM, as well as a few toys), Cam Clarke voiced him in the sequel (due to him being an adult), and Parker Gloris played him in the prequel and the ''KingdomHearts'' series.
** Buddy Hackett did not return as Scuttle for the TV series, so MauriceLaMarche filled in.
* RetroactiveRecognition: Ariel's VA would go on to voice [[WesternAnimation/ToyStory2 Barbie]] and [[CampLazlo Miss Doe]], among others.
** Chef Louie is René Auberjonois, years before becoming well-known as Odo on ''Star Trek: Deep Space Nine''.
* ThrowItIn: Ursula's "Pathetic." from her VillainSong lyrics aside to Flotsam and Jetsam was actually ad-libbed by Pat Carroll.
* WhatCouldHaveBeen: Or rather, what could have ''not'' been. See "ExecutiveMeddling" above.
** Ursula was originally intended to be played by [[Creator/JohnWaters Divine]], who died before he could record the role. Bea Arthur turned down the role because she was busy with ''Series/TheGoldenGirls'', and [[Series/AbsolutelyFabulous Jennifer Saunders]] auditioned but didn't get the role.
** In addition, Creator/MelissaFahn was originally supposed to play the role of Ariel, but was beat out by Jodi Benson.
** A deleted draft detailing an alternate version of the ending had Ariel and Flounder trying to rush to the wedding barge only for Glut (the shark from earlier in the film who got stuck in an anchor ring) to ambush them, causing Flounder to gain a second wind, deliver an already exhausted Ariel to the ship, and bait Glut into chasing him with the barrel still lassoed onto his back (hint: it's actually a gunpowder barrel), causing Glut to bite the barrel and get caught in an explosion.
** Broadway singer Elaine Stritch was the original voice of Ursula, but her constant clashing with the crew had her fired and replaced with Pat Carroll.
** Ariel was imagined as a blonde early on, but the animators didn't want to be seen as ripping off ''Film/{{Splash}}'' too closely.
** During the production of Ariel's Beginning: [[https://lh3.ggpht.com/_IJ2eVnEWWdA/S-xy8q-OnzI/AAAAAAAAABY/jlfrbKMdMgo/s1600/storyboard.jpg a storyboard]] from the film was presented. It appears that someone has Eric, Ariel and Sebastian hunting for a white whale and Sebastian isn't happy about it. There's also a woman in the storyboard who gets seasick like Grimsby in the beginning of the first film. It's implied that some talking parrot character will not get along with Sebastian and it's also stated that Ariel and Sebastian are "still angry with Eric". This was intended for another idea called [[http://animatedviews.com/2008/disneytoon-studios-and-the-sequels-that-never-were-with-tod-carter/ "Ariel’s Undersea Adventures".]]
* Ariel was originally going to lose her SeashellBra after first being transformed into human, and sport GodivaHair for the rest of the sequence. For whatever reason, this idea was abandoned.
* Fun Fact: Jodi Benson, the original Ariel, and Sierra Boggess, who originated the role on Broadway, both graduated from Millikin University.
** One of the models they used as a reference for Ariel's movements was Sherri Stoner, who would go on to voice Slappy Squirrel in Animaniacs. That's right: Slappy Squirrel was Ariel. Try wrapping your brain around THAT one...

!! The TV series
* TheOtherDarrin: Due to AuthorExistenceFailure, Ben Wright was unavailable to play Grimsby. He was replaced by another veteran character actor, Kay E. Kuter, in the TV series and ''Disney/TheLittleMermaidIIReturnToTheSea''.
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