Blue Submarine No. 6

A four-episode anime, taking place after the apocalypic flooding of Earth by Emperor Scientist Dr. Zorndyke. With the remaining cities ravaged by Zorndyke's army of fish-human hybrids - his "children" and intended heirs to the new world - the last hopes of humanity fall on the remaining submarine fleet, the titular No.6, and aquaphobic cadet-turned-slacker Tetsu Hayami.

"A sea of endless blue..."

Aired on Toonami back in its glory days.

Tropes used in Blue Submarine No. 6 include:

A God Am I: Subverted. Zorndyke doesn't think of himself as one because he thinks he is "not nearly so arrogant as that".
After the End: All coastal human cities are underwater as a result of Zorndyke's arctic melting.
Anti-Hero: Kino.
Anti-Villain: Zorndyke, depending on whether you sympathize with his motivations.
Apocalypse How: A Class 1. Zorndyke flooded earth's coastal areas. And he is planning to turn it into a Class 4.
Bittersweet Ending
Child Prodigy: Mei-Ling is ten years old and operates complex sonar machinery for a military vessel.
Conspicuous CG: Gonzo were never known for their ability to believably incorporate CG into their animated series. Blue Sub 6 is among their earliest efforts, so one might forgive them in this case - particularly as the rest of the animation is gorgeous.
Cool Ship: Blue Sub No. 6, and many others.
Cute Monster Girl: Mutio and the other fish-girls, as well as the furry girl at the end.
Cute Mute: Mutio, just about. The only word she can say is Hayami.
Emperor Scientist: Dr. Zorndyke is the poster boy for this trope.
Expy: Zorndyke is Dr. Moreau, more or less. See below.
Fan Service: Hayami's Shirtless Scene at his introduction and in the third episode, plus Kino's skin-tight body suit, which she often unzips halfway for some cleavage.
Fish People
Heroic Sacrifice: The Japanese SSGN that attacks the Ghost Ship.
Hot Sub On Whale Action: Most of the fight scenes.
Hopeless War
Humans Are the Real Monsters: Why Zorndyke created his fish-people and flooded the world in the first place.
- Zorndyke himself is probably by far the worst.
Interspecies Romance: Hayami and Mutio.
Literal Change of Heart: Turns out that Dr. Zorndyke removed his own heart and used it to power the Earth's destabilizing magnetic field.
Macross Torpedo Massacre
Mad Scientist: How the world (and a fair number of viewers) view Zorndyke.
Mermaid Problem: Averted. Implicitly.
Mickey Mousing: Hot Sub-On-Sub Action choreographed to bossanova. It's as awesome as it sounds.
Nice Job Breaking It, Hero: See below. No. 6, unintentionally, leads Verg and the Ghost Ship right to the secret base of Blue Fleet.
No Export for You: The very obscure prequel and sequel video games.
- To a lesser extent, a R2 UK release, or, to better put it, the lack of such.
No-Holds-Barred Beatdown: Verg to Hayami at the end.
- Not to mention the severe (though short) beatdown Mutio receives at the beginning of episode 4 (and just before the start of the episode) with a sheathed, heavy sword. Leaving her just enough strength to limp-swim away, bloody and injured.
Nuke'Em: Humanity's back up plan to finish Zorndyke.
- "So that's the plan? Nuke the psycho? THAT'S original" -Hayami
Ocean Punk
Our Mermaids Are Different: Mutio and her sisters.
Psychopathic Manchild: Verg. He wants to please Zorndyke, whom he calls "Papa", but is extremely violent and prone to throwing temper tantrums.
Recycled UNDER WATER!: The series is essentially a retelling of The Island of Dr. Moreau WITH FISH PEOPLE.
Scary Shiny Glasses: Zorndyke
Scavenger World: As a result of many of the former cities being underwater know.
Sci-Fi Writers Have No Sense of Scale: While 1 billion people seems like a lot, given the effects of the flood (enough to half-way sink a skyscraper) it should've killed a lot more. To get an idea: there are about 7 billion people currently in the world.
- The english dub over-corrects and claims 10 billion people died.
Silence, You Fool: Verg in the dub.
Soundtrack Dissonance: It's debatable whether the rather discordant, wailing jazz soundtrack fits the tone of the series.
Star-Crossed Lovers: Though at least it's implied by the final episode credits that Hayami and Mutio will eventually get back together once things finally settle down.
The End of the World as We Know It: What sets of the main plot of the series, is Zorndyke plan to reverse the magnetic poles of the earth, thus rendering it completely uninhabitable.
Transforming Mecha: The Grampus mini-sub.
Tsundere: Hayami. Mostly tsun.
Underwater Base: The headquarters of the Blue fleet. It is destroyed minutes after it is introduced, by Verg, who followed No. 6.
Underwater Ruins: See above. We see mostly Tokyo, but is implied that most of the world is flooded.
"Well Done, Son" Guy: Verg.
Well-Intentioned Extremist: Zorndyke.