Toki

A young boy, Sousuke, befriends a strange looking goldfish whom he names Ponyo. Unbeknownst to Sousuke, Ponyo is a magic fish who has decided that she wants to live with Sousuke and the other humans. Unfortunately, Ponyo's decision to give up her underwater life creates a crack in an ancient magic spell, and places the world in danger. Together, Sousuke and Ponyo must set…

In the far future, humanity has left behind an environmentally destroyed Terra and began colonization in order to reproduce their home. Humanity, now ruled by a super computer that controls the birth of children, sees the emergence of a new race called the Mu. The Mu, now hidden from the rest of humanity, have one dream, to return home, to Terra... Source: ANN

* Based on an animal shounen manga by Itagaki Paru.