The fish girl

a fairy tale about a selfish girl who catches a magical fish, disobeys its warnings, and is transformed into a fish herself. To regain her human form, she must embark on a quest to retrieve a crown stolen by a giant for the Queen of the Fishes. She undergoes several transformations to overcome obstacles and eventually restores the crown, which also frees other women from the sea who had been transformed into fishes by the queen's ladies.