Nadia: The Secret of Blue Water (or, "Fushigi no Umi no Nadia") is a 1990-91 anime produced by Gainax.
Nadia: The Secret of Blue Water (or, Fushigi no Umi no Nadia) is a 1990-91 TV anime series, later adapted as an anime film, produced by Gainax. It's about Nadia and her friends, who try to stop the Neo-Atlanteans with the help of Captain Nemo and his Nautilus.
The original anime TV series aired in April 1990 and consisted of 39 episodes. It was directed by Hideaki Anno and Shinji Higuchi. The anime film adaptation was directed by Sho Aono and was released in June 1991. Both were licensed and distributed by ADV Films in North America.
For more information about Nadia: The Secret of Blue Water: