a legendary ocean anime

6 Blue Submarine No. 6 Had An OVA Adaptation

Blue Submarine No. 6 was a post-apocalyptic manga series that was three volumes long. Despite the short length, it also had an OVA adaptation produced that was four episodes long. After the OVA adaptation was announced, the series was revised into five volumes under the name AO6.

5 Nagi-Asu: A Lull In The Sea Followed Humans Who Lived Underwater

Nagi-Asu: A Lull In The Sea, also known as Nagi No Asukara, followed seven friends. Some of them came from the sea, such as Chisaki and Hikari, while others came from the surface, such as Miuna and Sayu.

4 Nadia: The Secret Of Blue Water Followed Two Protagonists And Thieves Teaming Up To Stop Neo-Atlantean Forces

Nadia: The Secret Of Blue Water followed a young inventor named Jean and a circus performer named Nadia. The two of them were pursued by thieves so they could obtain Nadia's pendant, also known as the Blue Water.

3 High School Fleet Had Students On The Run After Accusations Of Mutiny

High School Fleet, also known as Haifuri, followed protagonist Akeno Misaki after she enrolled at Yokosuka Girls' Marine High School to become one of the highly-regarded female marines known as the Blue Mermaids.

2 Amanchu! Followed Two Girls Joining A Scuba-Diving Club

Amanchu! followed a shy young girl named Futaba Ooki who joined the school's Diving Club with the scuba-diving-obsessed Hikari Kohinata, despite Futaba not even knowing how to swim at all. After they both joined the Diving Club and learned to scuba-dive, they became close friends with each other and the entire rest of the club.

1 Mermaid Melody Pichi Pichi Pitch Followed Mermaids With Idol-Like Singing Powers

Mermaid Melody Pichi Pichi Pitch followed mermaid Lucia as she searched for a boy she rescued from a tsunami wave years before the story's current events. She did find him but unfortunately could not tell him that she was the mermaid or else she would turn into bubbles and disappear.