Watch The Incredible Mr. Limpet

Timid, self-conscious accountant Henry Limpet has little that brings him joy in life besides his obsession with fish. Henry would love to defend his country and tries to join the Navy only to be rated unfit. His best friend George Stickle had made the cut and been assigned his ship; while on furlough from the Navy George regails Henry with tales of life at sea.

While vacationing on Coney Island, Henry falls into the sea and is turned into a fish, his greatest wish in life. As a fish, he befriends Ladyfish who looks just like him and Crabby the hermit crab, and together they begin their adventures. He discovers his abilities and decides to help the Navy sink Nazi U-Boats, requiring the Germans to develop the limpet to compromise Henry while he's trying to assist the Navy.