It was animated by Studio Ghibli for the Nippon Television Network, Dentsu, Hakuhodo DY Media Partners, Buena Vista Home Entertainment, Mitsubishi, and distributed by Toho.

The film tells the story of Ponyo, a goldfish who escapes from the ocean and is helped by a five-year-old human boy, Sōsuke, after she is washed ashore while trapped in a glass jar.

It received critical acclaim for its uplifting themes, visual design, and simultaneous appeal towards young children and all audiences.

Fujimoto forces her back into her true form and leaves to summon Ponyo's mother, Gran Mamare.

Gran Mamare reassures him, and declares that if Sōsuke can pass a test, Ponyo can live as a human and the balance of nature will be restored.

When they reach the forest, however, Ponyo tires and falls asleep, and the boat slowly reverts to its original size.

Meanwhile, Gran Mamare grants Lisa and the residents of the nursing home the temporary ability to breathe in water.

[8] In 2004 and 2005, Miyazaki spent time in Tomonoura, a seaside town in Setonaikai National Park, where he familiarised himself with its community and environment.

[11] Initially, Miyazaki solely considered the concept of a film that would depict a stormy sea with "waves higher than the house on a hillside".

[12] Miyazaki recalled that as a nine-year-old he borrowed a copy of Hans Christian Andersen's "The Little Mermaid" from his neighbour, and that while he was reading it, he had difficulty accepting its premise that its protagonist did not have a soul.

[13] When preparing pre-production materials, Miyazaki hit a creative block before visiting the Tate Britain art museum, where he found himself startled by an 1852 painting named Ophelia done by English painter John Everett Millais and its attention to detail.

"[14] At the time Katsuya Kondō, Miyazaki's colleague, had been the animation director of House Hunting (2006), a 12-minute short film made for screening at the Ghibli Museum.

Kondō accepted an offer to work on the next Studio Ghibli feature film soon after completing the short, identifying an opportunity to progress the ideas behind House Hunting with more consideration to story.

[16] In normal productions, animating a sailing ship would usually involve drawing one cel and sliding it across the frame, which would fix it in a predefined perspective and direction.

[20] Ponyo's birth name, Brunhilde, is a deliberate reference to the eldest of the nine legendary Valkyrie and Wagner's Brünnhilde.

[21] Miyazaki wanted his next film to be a sequel to Ponyo, but producer Toshio Suzuki convinced him to make The Wind Rises instead.

Ōhashi was also the youngest participant in the 59th NHK Kōhaku Uta Gassen, beating Cute's Mai Hagiwara's record at age 11.

[25] An English-translated pop version of the theme was recorded by Jonas and Cyrus to tie in with the film's English release.

The score album, published on compact disc in Japan by Tokuma Japan Communications,[27] in South Korea by Pony Canyon Korea[28] and throughout Europe by Germany-based label Colosseum,[29] received a great deal of press in the West, including positive reviews from several veteran film music reviewers.

The film was released on VHS and DVD by Walt Disney Studios Home Entertainment on July 3, 2009, and on Blu-ray on December 8, 2009.

[40] The film's English dub was directed by John Lasseter, Brad Lewis and Peter Sohn of Pixar and produced by Frank Marshall, Hayao Miyazaki, John Lasseter, Steve Alpert, and Kathleen Kennedy; the English script was written by Melissa Mathison.

Miyazaki traveled to America to promote this film by speaking at the University of California, Berkeley, and San Diego Comic-Con.

[57] Anime Diet cited the quality of the translation, noting, "The story and the core of the film was communicated more than adequately through the professional dub and it did not get in the way of the sheer delight and joy that Miyazaki wanted to convey."

[59][60] Wendy Ide of The Times said Ponyo "is as chaotic and exuberant as a story told by a hyperactive toddler," and gave it 4 stars out of 5.

This poetic, visually breathtaking work by the greatest of all animators has such deep charm that adults and children will both be touched.

[64] It received a special mention in the Bologna Future Film Festival, for "the high artistic and expressive quality of animation able to give form to wonderful imagination of the worldwide cinema master".