Born as Brunhilde, the audience first sees her as a young goldfish who escapes from her father's underwater fortress and encounters a human boy named Sosuke. After he rescues her and adopts her as his pet, she starts to love him, and refuses to go home to her father.
When Fujimoto forcefully takes her home, she rebels and they have an altercation; she refuses to let him call her by her birth name, saying that her name is "Ponyo", which was the name Sosuke gave her. She even goes as far as to say that she wants to become a human, which disgusts her father, who is repelled by humans and their tendency to pollute the ocean.
Powers and Abilities
Ponyo displays water-related abilities, such as being able to speak to sea creatures or walk on the surface of the water, as well as breathe in it, even in her human form.
Ponyo seems to suffer from narcolepsy, apparently as a result of her transformation, and she seems to have greater difficulty retaining human form while using other abilities at the same time. Eventually, she becomes human after kissing Sosuke. It should also be noted that Ponyo loves ham.