A Tropical Fish Yearns For Snow (Nettaigyo wa Yuki ni Kogareru), is a manga by Makoto Hagino.
After Konatsu Amano's father transfers overseas for his job, she moves to a town by the sea in Ebisu Prefecture. While there, she meets an older girl named Koyuki Honami, who's well-respected as an honor student but like Konatsu, has no real friends. Koyuki also runs the Aquarium Club, which Konatsu ends up joining to satisfy the school's requirement for students to join clubs, and this is the story of the deepening bond between the two.
The manga contains examples of:
- Ambiguous Disorder: Some readers speculate that Koyuki is on the autism spectrum, since while her issues with social interaction can partially be attributed to being pressured to be a model student, she also has difficulty considering Konatsu's feelings.
- Book-Ends: The first chapter is titled "Konatsu Amano Won't Get Sad. The penultimate chapter, the last with the Idiosyncratic Episode Naming, is titled "Koyuki Honami Won't Get Sad."
- Class Trip: Koyuki goes to Tokyo with her yearmates. Since the trip is only for second-years, Konatsu stays behind.
- Club President: Koyuki. In Chapter 28, after the club gets new members, some start calling her "President Honami," (unlike Konatsu, who generally just calls her "Honami-senpai.")
- Club Stub: The Aquarium club only has one member- Koyuki- at the start of the series. Since Koyuki will end up quitting the club to focus on entrance exams, the club's future is very much in doubt. That changes in Chapter 28, when first-years join.
- Defrosting Ice Queen: Koyuki, the "snow" hinted at in the title. While she isn't especially cold, per se, she's detached from others due to being a model student, and Konatsu helps her defrost.
- First-Name Basis: While Konatsu usually calls Koyuki "Honami-senpai," she blushes as she calls her "Koyuki-san" when asking for her at the Honami residence. She eventually starts calling her "Koyuki" on Koyuki's request, since Koyuki will no longer be Konatsu's sempai after graduating.
- Fish out of Water: Konatsu feels quite out of place after moving from Tokyo to a small town in Ehime, hence her status as the "tropical fish" in the title.
- Good Parents: Honami-sensei is a supportive father to his daughter Koyuki, despite his status as her teacher occasionally complicating their relationship.
- Identical Stranger: While in Tokyo, Koyuki meets a fellow high schooler, and mistakes her for Konatsu. The fact that the other girl is wearing Konatsu's school uniform helps sell the resemblance.
- Idiosyncratic Episode Naming: Chapter titles have the following three words or phrases: the character's full name, a negative verb (e.g. "Won't," "Can't," "Doesn't"), and a description of a certain action. For example, the first chapter is titled, "Komatsu Amano Isn't Sad," while the second is "Koyuki Honami Isn't Happy." Also, they're called "tanks" (as in fish tanks) instead of "chapters."
- Japanese School Club: A significant portion of the story is about the Aquarium Club. Konatsu joins partly because of her blossoming friendship with Koyuki, and partly because the school, being small, requires students to join clubs.
- Last-Name Basis: Apart from the Honami family, virtually everyone calls Koyuki by her last name.
- Lonely Together: The basis for Koyuki and Konatsu's friendship. Konatsu is a a New Transfer Student, while Koyuki is a model student who is viewed as unapproachable. Unfortunately, as Koyuki changes and opens up to others, Konatsu becomes afraid of being left behind, putting a strain on their friendship.
- New Transfer Student: Konatsu transfers from Tokyo to a small town in Ehime Prefecture.
- Odd Name Out: While most chapter titles contain negative verbs, Chapter 21 is titled "Konatsu Amano Was Feeling Sad." The final chapter takes this a step further, discarding the Idiosyncratic Episode Naming altogether and simply sharing the name of the series.
- Parental Title Characterization: Koyuki calls her father "Dad" at home, but has to call him "Honami-sensei" at school.
- Parents as People: Konatsu's father loves her, but his job doesn't make it easy to be there for her. He even considers quitting his job so that they can live together once again, a move that, while well-intentioned, would end up separating Konatsu from Koyuki.
- Reasonable Authority Figure: When Honami-sensei hears that Koyuki broke school rules by looking at her phone in class (since she's desperately waiting for Konatsu's reply to her text), he goes to talk about it and has a heart-to-heart discussion about Koyuki with her.
- Romantic Two-Girl Friendship: Koyuki and Konatsu have a fairly close and seemingly romantic friendship.
- School Festival: One is held in Chapter 13, and Konatsu has to put on a show for it.
- Senpai Kohai: Koyuki is senpai to Konatsu's kohai.
- Sick Episode: Koyuki gets sick just before the school festival.
- Transfer Student Uniforms: Konatsu wears a blouse, a neck ribbon and a skirt instead of her new school's uniform, which is a jumper, a blouse and a necktie. She continues wearing this uniform even after spending months at her new school, and knowing that she will probably be there permanently, but eventually switches to the school uniform.
- We Named the Monkey "Jack": Konatsu names the aquarium club's salamander after Koyuki, who Konatsu says reminds her of the salamander in the short story "Salamander."
- Yuri Genre: While not officially classified as such, Koyuki and Konatsu at the very least enjoy a Romantic Two-Girl Friendship, with no prospective male love interests in sight. The ending leaves their relationship apparently platonic, but the two are closer than most friends are.