The story begins September 1941 just before the attack on Pearl Harbor. Shy bookkeeper Henry Limpet loves fish with a passion. When his friend George Stickle enlists in the United States Navy, Limpet attempts to enlist as well, but is rejected. Feeling downcast, he wanders down to a pier near Coney Island and accidentally falls into the water. Inexplicably, he finds he has turned into a fish. Since he never resurfaces, his wife, Bessie, and George assume he has drowned.
The fish Limpet, complete with his signature pince-nez spectacles, discovers a new-found ability during some of his initial misadventures, a powerful underwater roar, his "thrum". He falls in love with a female fish he names Ladyfish, the concept of names being unknown to her, and makes friends with a misanthropic hermit crab named Crusty.
Still determined to help the Navy, Limpet finds a convoy and requests to see George. With George's help, Limpet gets himself commissioned by the Navy, complete with advancing rank and a salary, which he sends to Bessie. He helps the Navy locate Nazi U-boats by signaling with his "thrum", and plays a large part in the Allied victory in the Battle of the Atlantic. In his final mission, he is nearly killed when the Nazis develop a "thrum" seeking torpedo, and is further handicapped by the loss of his spectacles. He manages to survive using Crusty as his "navigator", and sinks a number of U-boats by redirecting the torpedoes. After the battle, he swims to Coney Island to say goodbye to Bessie (who has now fallen in love with George) and gets a replacement set of glasses. He then swims off with Ladyfish.
In the film's coda, set in the modern times of 1964, George (now a high ranking naval officer) and the Admiral are presented with a report that Mr. Limpet is still alive and working with porpoises. The two men travel out to sea to contact Mr. Limpet and offer him a commission in the United States Navy. It is unknown what became of the conversation, for the movie ends with a question mark.
This was the last film of Larry Keating and Charles Meredith. Both Keating and Meredith died not long after it was finished.
The film had its premiere on January 20, 1964 at the Weeki Watchee Underwater Theater in Spring Hill, Florida. It was the world's first underwater movie premiere. The film went into general release on March 28, 1964.
The film had its television premiere on CBS on December 29, 1968, as part of The CBS Friday Night Movies.
The Incredible Mr. Limpet was released by Warner Home Video on VHS in 1990. It has since seen three additional VHS releases. On December 3, 1994, the film wss reprinted on VHS. On October 1, 2002, it was released on DVD. On August 7, 2012, Warner Home Video released the film in high definition on Blu-ray Disc.
Both Don Knotts and Elizabeth MacRae (Limpet and Ladyfish) were employed in Andy Griffith's Mayberry franchises, respectively as deputy Barney Fife and Lou-Ann Poovie, Gomer Pyle's girlfriend in the later seasons of Gomer Pyle, U.S.M.C..
During World War I and World War II, there was a mine known as a limpet, a type of naval mine attached to a target by magnets named because of their superficial similarity to the limpet, a type of mollusk. "Das Limpet" was the German Navy's identification of Don Knott's character.
The USS Alfred A. Cunningham was the naval ship featured in this film. Another ship used in filming was the USS Galveston (CG-3), which was referred to as the USS Los Angeles in the film. The Los Angeles was offered for use at the time of pre-production planning, but was decommissioned in the fall of 1963, before principal filming began. Here lies a double anachronism, in that the Los Angeles was not commissioned until the fall of 1945, and the Galveston had been converted to a guided missile cruiser, and clearly shows her 1960's configuration with large radars and missile launchers in place of her removed gun turrets.
The project entered development in 1996 when Steve Rudnick and Leo Benvenuti were hired as writers for a remake of The Incredible Mr. Limpet. By 1997, Jim Carrey entered negotiations to star in the title role, and was confirmed in February 1998 with Steve Oedekerk hired as the writer and director. Knotts was aware of plans for the remake, which he wrote about in his autobiography, and offered his support. Roughly $10 million was spent on animation tests to digitally map Carrey's motion-captured human face onto a fish's body, which produced disastrous results. By March 1999, Oedekerk left the project following creative differences, while Carrey followed suit in July. In April 2000, Warner Bros. hired Beavis and Butt-head creator Mike Judge as director and co-writer, with Robin Williams, Chris Rock, Mike Myers, and Adam Sandler in consideration for the lead role. Filming was set to begin early 2001.
In June 2009, it was announced that Enchanted director Kevin Lima was attached to direct. In 2010, it was reported that Zach Galifianakis was in talks of the lead role. In March 2011, Richard Linklater entered negotiations to helm the project, and was announced as the director in January 2014. That same month, Femke Wolting and Tommy Pallotta had begun working on the design and animation on the project while Galifianakis will reportedly play the lead character. On July 8, 2014, it was announced that Jon Hamm, Danny McBride, Sarah Silverman, Kevin Hart, Josh Gad, Keegan-Michael Key, and Jordan Peele entered talks for various roles in the film. On August 4, Linklater left the project to concentrate on his next film That's What I'm Talking About (released in 2016 as Everybody Wants Some!!).
"I wish I were a Fish" (sung by Don Knotts in voiceover)
As mentioned above, this live-action/animated film was the last vehicle and only full-length feature film made by the original Warner Brothers animation studio. They animated everything below the water, while the live action segments take place above the water and were shot during production.
Henry Limpet and Ladyfish are colored blue and pink, respectively, because these are the traditional colors of masculinity and femininity.
Unfortunately, the waves of the ocean can be seen through Henry Limpet's chest when he is talking to his sailor friend in the small boat; this was the first time anything less than their usual perfection of form could be seen in a Warner Brothers animated vehicle.
This film is based on the novel Mr. Limpet, which was written by Theodore Pratt.