[[quoteright:250:[[HaremSeries http://static.tvtropes.org/pmwiki/pub/images/cit_anidb_seto_no_hanayome.jpg]]]]
[[caption-width-right:250:Do not let the above image fool you. It's far from serious.]]

->''Please laugh along. This is the beginning of young love''.

While on a visit to his grandmother's, a schoolboy named Nagasumi nearly drowns in the sea. Before passing out, he catches a glimpse of a young mermaid. Nagasumi is found on the rocks, but no one believes his mermaid story... until that young girl, Sun Seto, appears at his home, asking Nagasumi to take responsibility for what happened by marrying her. Turns out that saving him broke the mermaid code of secrecy and one of them must be executed to preserve it, so Sun [[TakeAThirdOption chose a third option]] by proposing marriage.

Unfortunately, Sun is also [[MafiaPrincess the daughter]] of a mermaid {{Yakuza}} clan, and her [[OverprotectiveDad fiercely-overprotective father]] and several other clan members are not happy with the engagement and would rather just have him killed and be done with it. And there is also the matter of keeping it a secret that Sun is a mermaid as she starts attending his school. Then of course there's the matter of Sun's pint sized body guard who would like nothing better than to murder Nagasumi. Oh, and Sun's family decide it's a great idea to off some of the staff at Nagasumi's school and take their place so they can better watch Nagasumi. [[HilarityEnsues Do we really have to say it?]]

The manga started in 2002, ending in 2010 with 16 Volumes. A 26-episode TV series aired in early 2007, and a set of two [=OVAs=] followed.

The anime has been licensed by {{Funimation}} under the title ''My Bride is a Mermaid''. All 26 episodes of the anime, both subbed and dubbed, can be seen at Funimation's site [[http://www4.funimation.com/video/?page=show&b=295 here]] and [[http://www.hulu.com/my-bride-is-a-mermaid here]]. The full series is available on DVD.

A [[Characters/SetoNoHanayome character sheet]] for this series is under construction.
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!!This series provides examples of:
* AbuseIsOkayWhenItIsFemaleOnMale: Subverted. Abuse of any kind is PlayedForLaughs, but someone "will" call them out on it and stop them.
* AccidentalMarriage: At the beginning of the show, Nagasumi is proposed to by Sun, because as we find out, Sun (or Nagasumi) would have been executed for breaking the mermaid code, after she saves Nagasumi from drowning.
* AccidentalPervert: In episode 3, both Sun and Nagasumi walk in on each other in the bath within the space of 24 hours. Nagasumi winds up with broken ear drums (and an unwarranted reputation of being a deliberate pervert) both times.
* AdaptationExpansion: Episodes 25 and 26 of the anime combine Chapters 29 and 32 of the manga into an epic GrandFinale, though his TheReasonYouSuckSpeech comes from Chapter 60.
* AdaptationalVillainy: Minamoto no Yoshiuo, who is a one-shot character in the manga, was turned into the anime's BigBad. [[spoiler: As of Chapter 70, this seems to be the case in the manga as well, as it is revealed he is the one behind the "break Nagasumi and Sun up at all costs" mission.]]
* ADayInTheLimelight: Episode 17 dealt with Akeno. [[LampshadeHanging Nagasumi and Sun notice they didn't get many lines on this one]].
** Episode 15 focuses mostly on the class president, who up until this point was largely a minor character.
** Episode 24 hilariously gives the spotlight to Mikawa and his [[MistakenForDying terminal illness]].
* AdultFear: Some creep fakes a party to kidnap your precious only child and and knocks you out to prevent you from stopping it; as you go under you hear their sick desires for your child. Human or not, it's easy to feel the Seto clan's terror and anger when the mermaid noble fakes a get-together to nab Sun.
* AdultsAreUseless: ''All'' the adult authority figures, barring Masa-san and Ren Seto (Sun's mother).
** Parodied with the (remaining) school teachers during the club gang war. While the school becomes a war zone they make small talk as if truly unaware of it.
* AffectionateParody: Episode 10, which introduces Lunar's dad, is a parody of {{Terminator 2}}. Lunar's dad himself is a parody/ShoutOut to [[Creator/ArnoldSchwarzenegger Ah-nuld.]]
* AlwaysInClassOne: Sun's father arranges for all the students to stay in the same class for 3rd year so he won't have to memorize new names.
* AnnoyingArrows: When Mawari challenges Nagasumi to a card game and Sun and Saru join in, after an extremely brutal game, all of the characters are pretty much fine, except for Saru, [[CrowningMomentOfFunny sitting in the background with an arrow in his back.]] He's fine afterward for the rest of the episode of course, though.
* AnnoyingYoungerSibling: The [=OVA=]s introduce Satori, Saru's kid sister. Sun bonds with her over a love of action movies, and after Nagasumi rescues her from a collapsing theater, even she begins to think he's extremely manly.
** She actually appears much earlier in the manga.
* AnotherSideAnotherStory, PerspectiveFlip: In the Manga, Chapter 59, "Yakuza Wives: Conclusion" retells part of the first chapter from Sun and the Seto group's perspective.
* ArtEvolution: In the Manga, Kimura Tahiko's art style notably changed over the series' run. Compare the art in Volume 1 to that of Volume 9, and again to even more recent artwork. It's almost hard to believe these were drawn by the same person.
* ArtShift: Done fairly often by Nagasumi, into a semblance of ''FistOfTheNorthStar'' (see BattleAura below).
** Also done by people swooning over Masa.
*** [[LampshadeHanging Sun seems to have noticed that, too.]]
** The characters spend almost as much time art-shifted as they do in normal style; this applies especially to Nagasumi.
** At the very end of episode 26, Nagasumi seems to have permanently shifted into his FistOfTheNorthStar persona, at least until the OVA.
* {{Badass}}: Most of the Seto clan.
* BareHandedBladeBlock: Lunar's dad does this to Mikawa's blade in episode 10, with just a couple of fingers. Then he snaps the tip off before delivering a MegatonPunch to Mikawa.
* BattleAura: [[http://static.tvtropes.org/pmwiki/pub/images/cit_battle_aura_seto_no.jpg Like so.]]
** [[VisualNovel/GSenjouNoMaou Doesn't it remind you of a certain end of the century anime with a thug that has a mohawk?]]
* BattleDiscretionShot: Nagasumi fighting off all the San and Lunar fans during their singing duel. Seems they ran out of money to stage an epic fight scene so everyone was drawn as stick figures.
* BedmateReveal - In the middle of episode 7, which introduces Luna.
* BewareTheNiceOnes: Sun is generally a nice person, but if you tick her off, usually by picking on Nagasumi, watch yourself.
** In episode 18, after getting caught spraying water on Akeno/Nagasumi, Sun gives Maki a very stern lecture. Maki seems genuinely scared during that scene.
* {{BFG}}: Several. This show loves 'em.
** Kai once [[HyperspaceArsenal whipped out]] a missile launcher from nowhere for personal defense.
** Ren Seto shot her husband with a rocket launcher.
** The leading gangster of the run-down school in the OVA [[CurbStompBattle curb-stomped]] [[TookALevelInBadass powered-up Nagasumi]] with an RPG-7.
* BigBad: Though the series doesn't really need one for most of its run, it's eventually revealed that [[spoiler: Yoshio's the one who sent Akeno to evaluate the Seto gang in an attempt to break up Sun and Nagasumi, so that he can have her for himself, and even then he doesn't make an appearance until the last two episodes. Yoshio is introduced as a minor antagonist fairly early in the manga, and it also takes much longer for this revelation to occur.]]
* BigDamnHeroes: Two examples in the last episode. The first by the sub driven by Mikawa, which crashes into Yoshio's underwater palace and allows Sun's family (and Lunar's papa) to escape to do theirs to help Nagasumi a few moments later.
** Sun does one in episode 13 to stop Lunar's marriage to Nagasumi.
* BirdsOfAFeather: Saturn and Maruko. Both had Sun as their only friend when they were children. Both absolutely ''hate'' Nagasumi with a passion for daring to marry her (and as such take her away from them). It's no wonder they quickly became allies.
* BitchInSheepsClothing / ManipulativeBitch: Firstly, we're introduced to Maki, who acts cutesy towards Sun (she even has the tone and VerbalTic of [[RozenMaiden Suiseiseki's]]). However, aside from Sun and her boss (Sun's dad), she is very hostile towards everyone else, ESPECIALLY Nagasumi.
** Then, Lunar makes her entrance, and we don't have to wait long to know that her cute persona on stage is merely a facade.
** Both of them mellow out somewhat as the series goes along.
** Maki as "Chibi Lunar-Chan", [[BlatantLies subtly]] [[TheReasonYouSuckSpeech points out Lunar's flaws]] in episode 22 while she's putting on her ventriloquist act. They both get into an argument, then end up fighting each other hilariously. Amazingly, the class still thinks Lunar is just putting on a good ventriloquism act.
* BlackBlood: Not exactly black, but in the anime, all visible blood is colored a sparkly rainbow texture.
* BlatantLies: "Shibazaki-sensei is... ON MATERNITY LEAVE!"
** San's father does this a lot, particularly when it pertains to his feelings about Nagasumi.
** "I'm Britney, not a fish!"
** "I'm....not afraid of cats...."
* BlindWithoutEm: The class president. Because she changed her looks in episode 15, after Nagasumi accidentally stepped on her glasses, neither one of them are able to recognize each other.
* BlueWithShock: Happens to several characters, usually Nagasumi. Sun's in this mode in almost all of episode 16 when Akeno first shows up.
* BrainBleach: ''Everyone'' needs this when Lunar's dad starts going around in ''a sailor fuku.''
* BrandX: "Ningyonet Explorer". Did we mention mermaids have their own online shopping service?
* ButtMonkey: Several examples:
** Nagasumi to Sun's dad, most of her gang (except Ren and Masa), Lunar, and his parents.
** Sun's dad towards Sun, and especially his wife Ren.
** Chimp/Saru with practically everyone, but usually Nagasumi.
** Maki makes Lunar one in episode 22.
** Lunar's dad to Lunar. She almost never approves of anything he does.
** Nagasumi's dad to most of the cast, but [[HenpeckedHusband especially his wife]], who's made it quite clear that she's in love with Masa more than him.
* CallingYourAttacks: Mermaid songs.
* TheCameo: ''[[http://img135.imageshack.us/img135/1029/gokuinmbiam.png Goku]]'' from ''DragonBallZ'' appears in the background of a scene in Episode 18.
** Expies of who are suppose to be Vegeta and Trunks appear in the background together in one class room scene.
* CarnivoreConfusion: Sun and Lunar are disturbed when they take something with fish in it (with Sun asking if that makes them cannibals). But fish ''do'' eat other fish...
** Hilariously invoked with the three fish brothers during the Kyoto excursion.
** There's also the bit early in the show where Octopus Nakajima is teaching the home-ec class how to cook octopus, with what's heavily implied to be his own severed tentacles. Nagasumi wisely decides not to have a taste.
* CatchPhrase
** Sun: "The alternate way of reading Ninkyou (Chivalrous Spirit)... is Ningyo (Mermaid)!"
*** Rendered in the dub as "Honor amongst Thieves is Honor under the Seas!"
** Mawari: "Must [[ThirdPersonPerson Mawari]] teach you the rules of the *insert location here*?"
** [[ExactlyWhatItSaysOnTheTin "Shark"]] Fujishiro: "Can I eat him/her/them?"
** Akeno: "How vexing."
* CatSmile: Saru has one, although according to the other characters he's supposed to be a monkey. Lunar often has one as well.
* CerebusSyndrome: Well not exactly, but the last episodes tend to be more serious (and [[CrowningMomentOfAwesome awesome]])...or at least parody the more serious scenes.
** Last episodes? 13 was pretty hard hitting.
* ChekhovsGun: The ring from episode 2 plays a very important role in episode 26.
* CherryBlossoms: [[LampshadeHanging Lampshaded]] by Nagasumi after a few times of hearing Sun giving her "Honor among Thieves is Honor under the Seas" line.
** [[LeaningOnTheFourthWall And the other characters are constantly wondering where these cherry petals are coming from...]]
** It seems she got it from her mother.
* ClassTrip: The Kyoto arc (Episodes 18 and 19 in the anime, and Chapters 26-29 in the manga).
* ClingyJealousGirl: Mawari, Lunar, even Sun has shown this (episode 2, although played for laughs).
** Mawari even goes so far as to interrogate Nagasumi's relationship with Sun in episode 6 when she sees them leaving his house together.
** Mawari (again), the class president, Lunar, and Akeno all exhibit this trope after drinking that special potion that makes you act out your innermost desires in episode 19. HilarityEnsues as they chase him down.
** At the end of episode 26, after watching Sun and Nagasumi make up, Lunar doesn't seem too happy, and hilariously knocks out her dad to vent her frustration.
* CompellingVoice: The voice of a mermaid can arouse all sorts of emotions.
** Or blow your Eardrums / Car away.
* ConflictBall: Nagasumi randomly acting uncharacteristically douchy toward Sun sets up the climax for the series.
* CoolCar: Ren Seto is shown driving a Lamborghini at one point.
* CouchGag: The opening poem changes changes slightly every few episodes.
* CrouchingMoronHiddenBadass: While it takes 25 episodes for his the full extent of his Badass come out of hiding, in the second episode, Nagasumi ''suplexes Shark Fujishiro'' by '''grabbing him by the teeth'''.
** He also manages to erect a "Nagasumi Barrier" when Mawari attempts to throw water at Sun in episode 6 by basically jumping in front of the water before it hits Sun.
* CryCute: Most of the girls, particularly Sun and Lunar.
* CurbStompBattle: Nagasumi vs. Yoshio [[spoiler: once the former takes [[TookALevelInBadass several thousand levels in badass]] out of sheer rage.]]
* CuteMonsterGirl: Mermaid appearance here resembles that of western mermaids. The mermen in their true forms tend to resemble traditional Japanese mermaids, which are horrors straight from the [[Film/CreatureFromTheBlackLagoon Black Lagoon.]] And no, not ''[[Manga/BlackLagoon that]]'' Black Lagoon.
** Maki plays this even further, being knee-high to a pencil and all.
* DatingSim: "After School Love Heart", played by Sun and Lunar 's fathers and their associates in an attempt to understand how a girl's heart works. What happens next...(see MoeMoe entry below)
* DancingTheme: The opening. The first OVA's opening is also a dancing theme, but not the show's own. Rather, it's a pastiche of ''LuckyStar'''s opening.
* DefeatMeansFriendship: Lunar seems to mellow out somewhat in the second half of the anime series.
** Mikawa after his introductory episode.
* DemotedToExtra: In-universe example, Nagasumi's dad hilariously gets pushed further and further away from relevance.
* DisproportionateRetribution: A lot of the male characters are often on the receiving end of this, but Nagasumi has it the worst out of all of them.
* DoesThisRemindYouOfAnything: Shiranui and, later, Sun attempting to resist their spontaneous change to mermaids when their legs are doused with water. Full package of moaning, blushing and easily misunderstood dialogue. The first scene even has severe weakness of the legs (Justified in that her legs are changing, but still can't help but look like something else).
** In the first episode: "I need you to take responsibility for what happened earlier today!". If a young girl said that, with the same intensity, what is a parent going to think?
** In the final episode, Sun is wearing a wedding dress, while Nagasumi is wearing a black coat over his school uniform. The resulting visual when they hug makes Nagasumi look like he's wearing a wedding kimono as well.
* DoesNotLikeMen: Most of the female members of the school. To be fair, the guys at the school aren't exactly likable.
* EarlyBirdCameo: Mawari, Mikawa, Lunar, the Class President, and Shiranui all appear in the opening's dance sequence, in some cases ''long'' before they appear in the show itself.
* EvenTheGuysWantHim: Nagasumi keeps swooning over Masa.
* EveryoneCallsHimBarkeep: The class president, and to a lesser extent, Lunar's dad.
* EvilPlan: Averted for the most part in the anime. The bulk of the series is about Sun and Nagasumi's growing relationship, but once [[spoiler: the mermaid exam starts]] then a continuous {{plan}} by a villain shapes the remainder of the series. [[spoiler: A merfolk nobleman wants to add Sun to his harem and needs her to break with (or otherwise seperate from) Nagasumi to make that happen.]] It takes much longer for this to be revealed in the manga.
* EvolvingCredits: The first ending. The picture briefly comes back in the final episode with the additions of Akeno and the kitten.
** The opening also changes who's dancing from time to time as well, although Sun is always in the front. The ending adds new characters as they're introduced as well.
* {{Expy}}: Lunar's dad practically '''is''' TheTerminator, albeit with blond hair.
** Lunar herself seems very similar in both personality and appearance to [[VideoGame/DisgaeaHourOfDarkness Etna]]. In episode 9, she even sprouts an Etna-esque demon tail for a few seconds.
*** One of the [=OVAs=] also has her sporting miniature bat wings for a while.
* EyeCatch: The water color painting of Sun that pops in the middle of the episodes. She looks pretty BadAss in it as well.
* EyesAlwaysShut: The bartender in the Masa Today segments, which only open once in the entire series.
* FaceDeathWithDignity: In the first episode, Sun is perfectly willing to accept death as a result of saving Nagasumi and exposing the merpeople's existence to humans. Fortunately, Ren decides to TakeAThirdOption.
* FanDisservice: Unless you find big, muscle-bound men in tight, school/girl uniforms sexy.
* FanService: Although, admittedly, not a whole lot compared to most Animes out there.
* FirstGirlWins: Although it's something of a ForegoneConclusion, despite the fact that multiple girls from the school express interest in Nagasumi (though not necessarily to his face), and although he does occasionally waver, it's pretty clear from the beginning that Nagasumi has a strong mutual dedication to Sun.
* FirstKiss: Nagasumi's. You'll find out soon enough, and the anime [[RunningGag won't let you forget it]].
* GeckoEnding: The anime follows the manga with minor alterations up to Chapter 28 and then diverges wildly, with the manga carrying on with zany SliceOfLife stories involving Sun's numerous often-{{yandere}} {{Forgotten Childhood Friend}}s and the anime veering into a RescueArc where [[spoiler: Sun is abducted]], with some of the new characters from the manga being belatedly introduced in the [=OVA=]s. [[spoiler: Starting at Chapter 68, however, the manga starts to [[BroadStrokes generally follow the path of the anime's finale]].]]
* GenkiGirl: Lunar and Maki do this from time to time.
* GivingUpTheGhost: This happens to Chimp Sarutobi on a few occasions.
** Mikawa does this when he's on the boat with Mawari in episode 15.
*** Also Sun during the "Mermaid Exam"
---> '''Akeno''': (''as a chibi, winged Sun is perched on Sun's head'') Your soul is slowly escaping.
* GoldenSnitch: After seeing that his beloved daughter's team is losing the school athletic competition, Sun's father announces that the final race will be worth [[{{Pun}} 333]] points.
** Which also is an IncrediblyLamePun since 3 is pronounced "san" in Japanese.
* GratuitousEnglish: Lunar's dad is a walking ''factory'' of this trope. The most memorable being: ''[[CrowningMomentOfFunny "Masatsu Za Human!! TERMINATE!!]] [[http://www.youtube.com/watch?v=bAelnLrZcNE ("Kill the Human!! TERMINATE!!") ]]
** Mikawa's private army fits this trope as well.
** The "Secret Tail Deluxe" commercial in episode 11 also qualifies.
** Choco-Banana! [[http://www.youtube.com/watch?v=33yjIcB7Ebs OOH GREAT!]]
** Lunar's bodyguards (the black pair, not the classmate horde).
** Saturn's English lesson video. Probably NSFW due to the profanity she teaches, but very hilarious. "Good morning maggots!"
* HeelFaceTurn: [[spoiler: Akeno]] does a spectacular one in episode 26, and a corresponding one in Chapter 69 of the manga.
* HeroicBSOD: Sun suffers a particularly brutal one in episode 13, after [[spoiler: [[ShotgunWedding Nagasumi is forced to marry Lunar.]]]] Lunar gloats about it to her, but since she knows what Nagasumi really did, and how he really feels, even she feels a bit disgusted at herself at what's going on.
* HeterosexualLifePartners: Kai and Saru, [[UpToEleven to the extreme.]]
* HighPressureEmotion: Embarrassment -- Sun after posing in front of a mirror with [[MoeMoe cat ears on]], and Lunar after someone hints that she might be [[SchoolgirlLesbians in love with Sun]].
* {{Homage}}: Lunar's father, who is more or less [[LawyerFriendlyCameo The Terminator]] is introduced as an important character in episode 10. [[http://static.tvtropes.org/pmwiki/pub/images/cit_seto_no_hanayome_homage.jpg Yes, ''really''.]] There are many other parodies and homages in the series, including UC Gundam, ''Fist of the North Star'', and Neil Armstrong.
** And then there's [[BruceWillis Bunta Willis]], whom Sun is a [[Film/DieHard die]] [[IncrediblyLamePun hard]] fan of.
* HopelessSuitor: Pretty much any girl not named Sun, [[spoiler: although Lunar ''does'' almost succeed in roping him into a ShotgunWedding of her own]]. The class president in particular is a tragic case, as she's [[ShrinkingViolet incredibly shy]] around Nagasumi, and in episode 21 of the anime, she finally manages to write a love letter to Nagasumi. But her efforts are both sabotaged by her classmates, and later Sun's dad/Maki. While PlayedForLaughs, you can't help but feel a little sorry for her making such a fool of herself given how much courage it must've taken her to do this.
* ICanExplain: "THIS IS JUST A MISUNDERSTANDING!!!" Spoken by Nagasumi, many, many times.
** He unfortunately always rolls a natural zero in his diplomacy checks.
* ImplacableMan: Lunar's dad for the most part (except if Lunar hits him). Nagasumi in the last episode.
* IncurableCoughOfDeath: Maru seems to suffer this from time to time. She's arguably ''much'' better now though, than during the time she stayed with the Seto clan.
* InnocentCohabitation: Sun decided to move to her fiancé's house, which upset her father to no end.
* InstantFanClub: The males at the school are divided into two large, militant, warring fan clubs over Sun and Lunar. Lunar personally leads her club in efforts to take over the school. Mawari is left leading an equally-violent third club comprised of the girls, united under 'restoring order' with the motto "All men are beasts."
* InvoluntaryDance: Festival Dance.
* InvoluntaryShapeshifting: Young mermaids' legs automatically revert back to tails when they get wet, and revert back when they're dried off. According to Akeno, it's like trying to hold in a sneeze.
* InterspeciesRomance: Nagasumi and Sun mainly, but the series' LoveDodecahedron also contains another mermaid and an orca, [[spoiler: and the mermaid noble that captures Sun and tries to marry her against her will at the end of the anime is actually a catfish.]]
* IronButtMonkey: Nagasumi for the most part. Saru fits this trope as well, being able to take various punishments from many characters (usually Nagasumi).
* ItMakesSenseInContext: Applies to probably roughly 80% of this show.
** And a lot of the other 20% MakesJustAsMuchSenseInContext.
* {{Kawaisa}}: Examined, given the sheer number of [[BitchInSheepsClothing seemingly cute, innocent girls]] who talk in super-high voices trying to seem cute.
* KillSat: Property of NASA.
* LampshadeHanging: Done a lot through the series; notably when Nagasumi points out the falling cherry blossom petals that surround Sun when she is getting chivalrous. In one instance he asks where the petals keep coming from (they were on a boat in the middle of the ocean at the time), and in another he waves them away while trying to calm Sun down.
* LargeHam: Yakuza grunts, their boss Gozaburo, and his daughter Sun. She's not as bad as the rest of the outfit but get her in a "Honor among thieves" mode and watch the cherry blossoms materialize.
** Nagasumi even lampshades this when he asks Sun where the petals are falling from in episode 3.
** Sun's dad gets particularly hammy during the Kyoto excursion episodes.
** Virtually anyone arguing with Nagasumi ends up doing a [[HamToHamCombat ham-duet]] with him, especially Mikawa early on.
* LawyerFriendlyCameo: Sun is a big fan of the Hollywood actor [[BruceWillis Bunta Willis]], who has a film coming out in episode 15.
* LemonyNarrator: "Cops vs Thugs" has the narrator snarking at events and character's lines.
* LethalChef: Lunar's onigiri (rice balls) in episode 9 doesn't look particularly tasty, despite Nagasumi's mom helping her to make them.
* LetHerGrowUpDear: Compared to her [[strike: borderline]] psychotic husband Gozaburo Seto, who has a tendency to send ''assassins'' after his son in law Nagasumi, Ren Seto was absolutely delighted when she mistook his drying of her daughter Sun's fins as public sex ("My oh my, kids will do it anywhere these days."). She provides (not so) helpful love potions to speed up their blossoming marriage along with advice and encouragement, when she's not occasionally trying to seduce the boy herself, that is.
* LoveBubbles: They tend to show up during lovey-dovey scenes.
* LoveDodecahedron: Mawari and the Class Rep have crushes on Nagasumi, who is dating/engaged to Sun (but sometimes has to admit that Masa's lookin' kinda cool) while Lunar tries to secure him for herself due to a rivalry with Sun, who -- the entire male population of the school in general aside -- is also being pursued by Kai Mikawa, one of her childhood acquaintances, who in turn has most of the female student body swooning over him.
* LoveObstructingParents: Because it's traditionally funny that Sun's family either tries to kill Nagasumi or seduce him (or teach him how to seduce); and Sun doesn't notice most of the time.
* LoveEpiphany: Mawari has one towards Nagasumi in episode 6 when she gets confused as to why she gets a little distraught at seeing him and Sun together.
** Both Lunar and Sun have one in episode 13 when they both do a LoveConfession to him.
** Akeno realizes she's falling in love with Nagasumi in Chapter 56, though her sense of honour regarding her mission conflicts with it until Chapter 68.
* LoveLetterLunacy: Episode 21. Practically all of the major characters seem a bit too interested in who wrote said letter to Nagasumi.
* LovePotion: With the side effect of every guy that sees him hating him, in episode 21.
** We even get to see on what the various females' view of the "ideal man" is...except Maki's, [[{{Squick}} though this is probably for the best]].
*** [[PsychoLesbian Assuming she even]] ''[[PsychoLesbian likes]]'' [[PsychoLesbian men]].
* LoverTugOfWar: Sun and Lunar do this to Nagasumi in episode 7 and 9
* MadeofIron: Lunar's dad. Played straight for the most part, since he's able shake off things such as being hit with a rocket launcher and a KillSat (courtesy of NASA), and even withstands Sun's dad's attacks. It's averted whenever Lunar hits him.
* MafiaPrincess: Sun. Lunar is technically one too, but doesn't seem to be involved much in her father's business. Maru, another of Sun's childhood friends, is also one of these, except for a family based up in Hokkaido.
* MagicalGirlfriend: Sun is beautiful and sweet and devoted to the protagonist, Nagasumi. She's also a mermaid with a super sonic screech attack.
* MagicMusic: Presumably all mermaids can do this but we only see Sun, her mom, and Lunar.
* MakeMeWannaShout: Possessed by all female mermaids, apparently (Lunar does it often, and both Akeno and Ren do it in the finale).
* ManlyTears: Episode 24, srsly.
* MarriageBeforeRomance: San and Nagasumi's marriage… either they got married, or one of them would have to die.
* {{Masquerade}}: Secret existence of mermaids.
* MeaningfulName: Nagasumi's pal/Kai's lackey Hideyoshi Sarutobi, whose family name literally means "Jumping monkey", and whose given name is a reference to a RealLife [[UsefulNotes/ToyotomiHideyoshi feudal lord]] who had "Monkey" as his nickname. Guess what he looks like.
* {{Meganekko}}: The class president.
* MegatonPunch: Lunar seems to enjoy giving these out, mostly to her dad and Nagasumi. Sun's mom does this to her husband a lot too.
* MeleeATrois: Sun's Fan Club VS Lunar's Fan Club VS the Displininary Committee (virtually all of the female student body)
* MistakenForCheating: A NotWhatItLooksLike moment between Nagasumi and Lunar leading to a ShotgunWedding imposed by Lunar's father.
* MistakenForDying: In Episode 24, some of the students catch Mikawa leaving a clinic. Later Saru overhears an out-of-context conversation between the doctor and a nurse, and assumes that Mikawa must have a terminal illness. Eventually even Mikawa comes to believe he's dying, and seems at peace towards the end. Then they find out what he really had, and [[StatusQuoIsGod everything reverts back to normal, more or less.]]
* MoodWhiplash: The end of episode 12, which starts out comical, then suddenly shifts to being serious as Nagasumi is forcefully taken away from Sun.
* MoreDakka: Maki's conchshell gun seems to operate on this. In one episode, Sun's dad also has a machine gun in episode 8, which served no purpose other than to shoot up Nagasumi's house. Lunar's dad also uses a gun when shooting at Nagasumi in episode 12.
* MushroomSamba: Episode 19 has all the girls (and Saru) drinking Uoihatsu, forcing them to "[[ShoutOut act on]] [[CommandAndConquer instinct]]". In other words, they got drunk.
* NewTransferStudent: Sun, Lunar, Kai, Akeno...and that's not counting Sun's family replacing half the school staff.
** The cast starts {{lampshading}} this after the first few transfers.
* NiceGuy: Nagasumi for the most part. Which is partly why so many of the female characters, such as Lunar and the class rep, are attracted to him, even if they think he's only average in looks and brains.
* NobleWomansLaugh: Lunar, often with a goofy looking face.
** Maki hilariously mocks Lunar in episode 22 with this trope as "Chibi Lunar-Chan".
* NotWhatItLooksLike: Early on, Nagasumi tries to dry Sun's legs using a rather compromising position.
** Later, an even worse case of this almost leads to a ShotgunWedding with Lunar.
** When Nagasumi and Mawari saw Sun and Akeno undergoing endurance training together in the bathhouse, the two mermaids looked rather... provocative. This becomes a running gag with Mawari catching them in compromising positions and [[MistakenForGay thinking Akeno is a lesbian]].
** At one point, Nagasumi's dad sees Sun from behind and stares longingly at her, thinking she was his wife. His wife then comes and beats him up for being a pervert.
* NunTooHoly: Sun's ''other'' childhood friend (she seems to have a lot of these) Maruko Okhotsk, wears a customized nun's habit. Which is odd, considering the religion she follows isn't Christianity at all, but something akin to what the Ainu people of northern Japan believe in.
* OfficialCouple: Nagasumi and Sun are ''very'' committed to each other, in spite of all the LoveDodecahedron shenanigans.
* OnceAnEpisode: Masa does something kinda cool, and Nagasumi and/or his mother swoon over him. Sun gives her CatchPhrase (or similar) in a dramatic voice in a spotlight amidst falling [[CherryBlossoms cherry blossom]] petals. Nagasumi narrowly escapes death. Not so much in the second half.
* OverprotectiveDad: Sun's father takes this to a [[strike: borderline]] '''truly''' ''psychotic'' level. Lunar's father is more stoic, but just as dangerous.
* OvertookTheManga: Ostensibly the reason for the anime's GeckoEnding.
* PantyShot: The only viewer-perspective example of this occurs when [[FanDisservice Lunar's Dad dressed as a Schoolgirl]].
* PapaWolf: Gozaburo comes in swinging when he believes that Lunar's Papa is posing a threat to his precious Sun.
* PaperThinDisguise: When Sun does a GenderBender and acts like a guy in episode 22, absolutely no one is fooled, from Saru to her dad. In fact they all question why she's dressed like that.
** Nagasumi sees right through the fish brother's disguises when they first show up, as well as when one of them dresses up like a schoolgirl.
* ParodyCommercial: Some of the wackier situations needs a product from the Seto Mermaid Company itself. To order, [[FiveFiveFive dial]] [[RidiculouslyLongPhoneNumber 000-1425-XXXXXX-74X5-00XX]].
* ThePiratesWhoDontDoAnything: It's a wise choice on the part of the director to ''not'' show just ''how'' Yakuza '''really''' make their money; Sun's family would really be ''nowhere'' as fun and lovable to watch if they are drug smuggling, gun running, prostituting extortionists who commit murder on a daily basis. Of course, after the first episode, the entire clan essentially dedicates itself to trying to ruin Nagasumi's life, so they don't have time to do any of that stuff.\\
The most villainous thing the Seto Syndicate seems to do is run a shopping channel that seems to be selling "Fin Weights", porn (fish porn at that, for mermaids, see?) and Lance of Longinus copies. There ''was'' a goldfish scoop booth at a carnival in Episode 2. Nagasumi reasons that since the guy who ran the booth [[CarnivoreConfusion was an aquatic creature himself]], it could possibly count as trafficking.
** They, at least, hint at the "killing on a daily basis"-business, with assassins such as [[LittleMissBadass Maki]] trying to off Nagasumi on a daily basis.
** Really (and given the story, this probably shouldn't come as a surprise) the biggest asshole is a member of the Government.
* PolarOppositeTwins: Lunar and Sun, [[MeaningfulName get it?]]
* PowerNullifier: Maruko's ''Silent Voice'' can nullify any of Sun's mermaid songs, including the ''Song of the Hero'' she usually uses to buff up Nagasumi.
* PrettyFreeloaders: Sun, Maki and Lunar are all staying at Nagasumi's house, moving him up to the attic.
** Partly subverted however, since both their families continually repair damage they cause to his house, and Lunar's father even renovates it while he was it. Nagasumi's mom in particular loves the new kitchen. Gozaburo still deliberately left them with their mortgage, though.
* RapeAsDrama: In the final two episodes of the anime Sun is abducted by a lecherous nobleman who drugs her into a stupor and intends to rape her.
* RealMenEatMeat: [[InvokedTrope Invoked]] by Sun during her TestosteronePoisoning stint.
* RealMenWearPink: Dating sim episode. Maki, at least, thinks its very manly to do something like that for one's boss.
* ReasonableAuthorityFigure: Ren and Masa are pretty much the only adults in the series who are actually more mature than than the kids are. Masa is basically the only character who actually performs well in his role as a teacher, and Ren is almost always the one to step in when she feels the situation is getting out of control.
* RescueRomance: Satori fell for Nagasumi by this.
* ResetButton: [[AvertedTrope Averted]] between episodes 11 and 12. At the end of episode 11, the house has been destroyed [[spoiler:by [[AttackOfThe50FootWhatever Giant Nagasumi]]]]. At the start of episode 12, we see everyone in the house like usual...however, it's quickly established that Sun's and Lunar's dads used their connections to have the house rebuilt between episodes (Nagasumi's mom even gushes about how much she loves the new kitchen!) [[spoiler:In fact, this indirectly leads into the WhamEpisode.]]
* RoyalWe: Lunar refers to herself as "We" out of arrogance.
* RuleOfFunny: This shows runs on this. Only the CrowningMomentOfHeartwarming Father/Daughter and Nagasumi/Sun moments are played even ''remotely'' straight, and even then subverted with a good-natured chuckle.
** I will calm everyone down with the Mermaid Lullaby!! [[CrowningMomentOfFunny Ralli-Ho!! Ralli-Ho!! Ralli Ralli Ralli HOOOO!!]] Truly, a yodeling mermaid is something you don't hear very often.
* RuleOfCool: The various fights taking place throughout the series, most notably the intentionally exaggerated GrandFinale.
* SeriousBusiness: The Sun vs Lunar fan club war. It almost tore the school apart.
** The dating sim episode 20. Both Lunar and Sun's dads end up cosplaying and getting a little too in-character with the visual novel they're playing, which freaks both of the girls out.
** Mawari tends to think of this too when trying to enforce school rules. It's not very effective most of the time.
** When Sun's dad pulls the fire alarm in episode 14 which causes several firetrucks to show up at the school. Mikawa also calls in some fighter jets. After Ren finds out they both did that simply because of a kitten, she beats them all up for going overboard, while Masa apologizes profusely for wasting the firemen's time.
* ShoutOut: The fat lady disguise and the quote "Open your mind" from the original ''Film/TotalRecall1990'', the Gate of Babylon from ''FateStayNight'' The Lance of Longinus from Anime/NeonGenesisEvangelion... and of course, TheTerminator.
** Mawari [[Franchise/LupinIII Zenigata]], who wants to be a join the police like her father, who is the superintendent.
** Nagasumi goes FistOfTheNorthStar on everyone's ass thanks to Sun's "Song of Heroes."
*** And again in the manga, telling someone [[YouAreAlreadyDead that their gender has already been changed]] when the last amazoness transformed a thug into a girl.
** The leader of Lunar's protection squad wears a mask and helmet very similar to [[StarWars Darth Vader's]], and in the manga [[LampshadeHanging he even appears on a karuta card paraphrasing one of Vader's famous quotes]].
** When Nagasumi starts his beatdown on Yoshiou in Episode 26, he shouts "[[TengenToppaGurrenLagann HISSATSU!!!]]", [[Manga/FistOfTheNorthStar rapidly punches him in the face dozens of times]], and when he finishes he has his [[VideoGame/StreetFighter back to his opponent with a flaming kanji emblazoned on his jacket]].
* ShotgunWedding: Having seen Sun in her mermaid form, Nagasumi is given two choices: marry her, or one of them will have to be executed... and Gozaburo ain't gonna let it be his precious daughter.
** When Lunar's dad walks in on her naked from the waist down and Nagasumi rubbing her behind with a towel,[[note]] ...having just been drying her off after she'd been splashed with water.[[/note]] Lunar takes advantage of the [[NotWhatItLooksLike ensuing misunderstanding]] to try to steal Nagasumi away from Sun.
* ShrinkingViolet: The class president.
* SkinshipGrope: "Must Mawari teach you the rules of the bathroom?" to the class rep. ''Everyone'' leans against the wall to listen.
* SleepCute: Sun and Nagasumi in episode 13.
* SolarAndLunar: Sun and Lunar tend to be associated with the sun and the moon for obvious reasons. Sun is an honorable woman and kind to everyone she meets while Lunar has a bit of a rotten side and is Sun's SitcomArchNemesis.
* SpeakNowOrForeverHoldYourPeace: Sun crashes Nagasumi's [[ShotgunWedding forced wedding]] to Luna - wearing a white kimono, sarashi, and carrying a katana - in order to take her fiancé back, even if it means renouncing her ties to her family and declaring war on the Edomae syndicate.
* SpellMyNameWithAnS: Sun/San and Lunar/Luna/Runa are the main cases, though most official material (And the Funimation translations) give their names as Sun and Lunar.
* SpitTake: Terminator, Saru and Masa-san~, in that order from the lies their kin use for ''moe'' appeal while [[FanserviceWithASmile working at]] a MaidCafe.
** Sun's mom Ren does one after seeing giant Nagasumi in episode 11.
* StormingTheCastle: Episode 26.
* SuperDeformed: Happens regularly throughout the series.
* SuperReflexes: Nagasumi has this from time to time. Such as whenever a character attempts to hit one of the mermaids with water, like Mawari on Sun, and later Maki on Akeno (although he fails to completely block her attacks). In episode 21, he also activates a super-evasive mode, allowing him to dodge all the hits from both Sun AND Lunar's fathers. [[{{Badass}} At the same time.]]
* SupportingHarem: Other than a close call with Lunar, none of the girls really have a shot at Nagasumi. It's pretty obvious that he only wants Sun.
* SustainedMisunderstanding: Episode 24 with Mikawa's visit to the doctor. See MistakenForDying for further details.
* TakeAThirdOption: "You saw my true form and know I'm a mermaid. I don't want to die, but I'd rather not kill you either. I know, let's get married..."
* TakingTheBullet: "Nagasumi Barrier!"
** Done more seriously in the final episode.
* ThemeMusicPowerUp: Sun's "Song of Heroes", being MagicMusic, actually ''causes'' this effect on Nagasumi. Used normally in episode 26, where Nagasumi [[CrowningMomentOfAwesome powers up by himself]] by virtue of being ''extremely pissed off'' and the music just plays as BGM.
** Lunar's "Song of Battle" has a... [[HatePlague less refined]] sort of similar effect.
* ThemeNaming: Times two yet. Mermaid characters will usually have an important body of water inserted into their family names (Seto Inland Sea, Tokyo Bay (Edomae), Shiranui Sea, Mikawa Bay, the Sea of Okhotsk), and a celestial object as their given one (Sun, Lunar, Akeno (Ake no Myoujo = Venus in the Eastern Sky), Kai (Kaiousei = Neptune)). Saturn in the manga is also added to the celestial list.
* TheObiWan: Masa often gives useful advice to several characters, usually Nagasumi.
* [[TheOnlyOneAllowedToDefeatYou The Only One Allowed To Eat You]]: Fujishiro the shark says that when the gang shows up to save Nagasumi from Yoshio's guards.
* TheReasonYouSuckSpeech: Lunar gives one to Sun, and Mikawa gives one to Nagasumi as well. Both are jealous that the other seems to have everything while they believe they have nothing.
* ThirdPersonPerson: Mawari with her catchphrase.
* ThisAndThat: Maki suggests that Lunar and Nagasumi engage in this when she catches them almost kissing each other.
* TransferStudentUniforms: Lunar and Kai.
* TransformationSequence: Luna and Sun change from elaborate kimonos into showy stage costumes magical-girl style, as lampshaded by Nagasumi. There's also the Class President's transformation into the "Last Amazoness".
* {{Tsundere}}: Lunar, Mawari at times.
* UnknownRival: Lunar is always trying to top Sun out of jealousy.
* UnluckyChildhoodFriend: Mawari towards Nagasumi, Mikawa towards Sun.
* UnusuallyUninterestingSight: The teachers' reactions to the Sun vs. Lunar riot that tears apart the school is surprisingly apathetic.
* UnwantedHarem: Sun, Lunar, Mawari, Akeno, [[EveryoneCallsHimBarkeep the class president]], [[HugeGuyTinyGirl Maki]], [[GayOption Masa]]... and that's not even addressing the characters exclusive to the manga.
* VillainProtagonist: See CardCarryingVillain above; it's REALLY easy to forget that these are {{Yakuza}} that we are laughing with.
* XMeetsY: Creator/RonHoward's ''Film/{{Splash}}'' with {{Yakuza}}...
** ThisIsYourPremiseOnDrugs: ...on crack...particularly strong crack ... no this is not on crack... THIS IS CRACK!!
* WhamEpisode: Episode 12 and 13, which focuses on Sun and Nagasumi's relationship and feelings with each other.
* WhatHaveIDone: Akeno has second thoughts about inviting Sun's family to Yoshio's "party" when she realizes how much of a JerkAss Yoshio is.
** Lunar seems to invoke this trope shortly after gloating over stealing Nagasumi away from Sun in episode 13.
* [[WhyDidItHaveToBeSnakes Why Did It Have To Be Cats]]: Sun's dad, despite being a Yakuza leader, still has his childhood fear of cats. Taken to hilarious extremes when the cat's he deathly afraid of is still a kitten.
** Most of the mermaids have this, and it's justified in that they ''are'' technically fish. And cats love fish.
*** Particularly hilarious with Maki. Although the kitten merely licks her, she acts as if she's going to be eaten alive, though she ''is'' bite-sized, making it a legitimate concern.
** Akeno, despite being a hardened swordswoman, is extremely afraid of ghosts.
* WifeBasherBasher: "How '''dare''' you point that thing at a girl! How dare you point that thing '''AT SUN'''!"
** This in itself is a reference to FistOfTheNorthStar, pointing weapons at helpless innocents was a good way to get Kenshiro pissed at you.
* WigDressAccent: The so-called [[MasterOfDisguise "shapeshifter"]], Furiyo.
* {{Yakuza}}: ''Mermaid'' yakuza, at that.
* YamatoNadeshiko: Sun is extremely devoted to Nagasumi, to the point that she decided to follow him to Saitama and [[InnocentCohabitation live under the same roof]] as his fiancée. She was even willing to bet herself for her future husband's contest. What truly sells it is when she [[spoiler: interrupts Lunar's ShotgunWedding]] while wearing a wedding kimono and carrying a katana, which she then uses to great effect.
** Nagasumi's grandmother is sweet and caring and strangely adaptable to the craziness that has invaded her family.
** Note that Sun, despite her YN traits, subverts it in the speaking department, at least in English. Instead of the formal speech patterns of more traditional [=YNs=] like [[Manga/AhMyGoddess Belldandy]] or [[Manga/AiYoriAoshi Aoi Sakuraba]], Sun has a more "casual" register, with contracted words and dropped final "g"s.
* {{Yandere}}: Scary, scary Lunar and Maki.
** Saturn from the manga and second OVA makes Lunar look positively harmless.
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