Pixar's characters are often planned years in advance. Nemo first appeared as a stuffed toy on a couch in Boo's room in Monsters, Inc. (2001). This movie introduces the main characters of post-2003 Pixar films. A boy in the dentist's office is reading a "Mr. Incredible" comic book, anticipating The Incredibles (2004). Luigi the car is driving by the dentist's office, anticipating Cars (2006).
Andrew Stanton pitched his idea and story to Pixar head John Lasseter in an hour-long session, using elaborate visual aids and character voices. At the end of it, an exhausted Stanton asked Lasseter what he thought, to which Lasseter replied, "You had me at 'fish.'"
Director Andrew Stanton did the voice of Crush the sea turtle. Stanton never intended to do the voice of Crush, only providing the voice for the film's rough cut, but when it proved popular in test screenings, he decided to do it for the final film. Stanton recorded all of Crush's dialogue lying on his couch in his office.
Director Andrew Stanton originally planned to reveal the fate of Marlin's wife gradually through flashbacks, seen periodically as the story unfolded. After a few early in-house screenings, he found that Marlin came off as too much of a worrywart, and decided to reveal the entire back-story up front, thus making Marlin more appealing by establishing the reason for his over-protectiveness. This idea would eventually be used in the film's sequel Finding Dory (2016), where Dory starts to have flashbacks about her family, and starts to remember who she is.
The look and feel of the underwater world was essential to the film's success. To that end, the production crew were all exposed to visits to aquariums, diving stints in Monterey and Hawaii, study sessions in front of Pixar's own 25-gallon fish tank and even a series of in-house lectures from an ichthyologist (the branch of zoology that deals with fish).
SERIES TRADEMARK: When Gil is thinking ahead about how he and the fish will escape, as the camera pans toward and out the window, the Pizza Planet truck from Toy Story (1995) can be seen on the outside. This is the first film where the Truck has a Distinctive Appearance, being a Right Handed Vehicle driving on the left side of the road, since it's in Sydney, Australia.
Dory does get Nemo's name right a total of seven times, four of them without being corrected first. Of course, some of these times are in quick succession. She also calls him Chico, Fabio, Bingo, Harpo, and Elmo, in that order.
Rendering a frame (at a resolution of 1600x900), which lasted about 1/24th of a second, in the film, could take up to four days because of the complexity of the underwater environment, with sunlight coming through the water and hitting fish scales.
Nemo's father Marlin was originally voiced by William H. Macy. According to James B. Stewart's book "DisneyWar," it was after seeing an early cut of the film with Macy's voice that then-Disney CEO Michael Eisner infamously told his board of directors, "This will be a reality check for those guys...It's OK, but nowhere near as good as their previous films. Of course, they think it's great. Trust me, it's not." Director Andrew Stanton recast the role of Marlin with Albert Brooks, and the film went on to get some of Pixar's best reviews ever and become the highest-grossing animated film of all-time. Even worse for Eisner, Disney's distribution contract with Pixar was close to expiring at this time and thus he was facing a difficult position of trying to renew it with Pixar's owner, Steve Jobs, who already loathed Eisner before that insult. That situation of Disney in danger of losing their most consistently successful producer of films because of Eisner's denigration proved to be one of the numerous complaints about him to finally prompt the shareholders to fire him.
Film makers were worried that comedian Ellen DeGeneres would not be able to perform the dramatic scene where Dory begs Marlin not to leave, so, at the end of a day of recording other scenes, they asked her to record a trial reading of the scene, with the intention that she go home with a recording of it to work on her actual performance. DeGeneres agreed, but her trial reading was so heartfelt and emotional that (apart from a few small edits) this is what was used in the final cut of the film.
Crush's son Squirt is voiced by Nicholas Bird, the young son fellow Pixar director Brad Bird. Director Andrew Stanton was inspired to cast Nicholas when Brad was showing home movies around the Pixar offices.
To see how realistic they could make it appear, the art team was asked to make exact copies of actual underwater and above-water shots. Ultimately, the results were simply deemed "too realistic" for a cartoon.
Albert Brooks was always Andrew Stanton's first choice to voice the part of Marlin. Although Brooks had done several episodes of The Simpsons (1989), he found voice work for a feature length cartoon to be substantially different in that he had to do it in isolation, and not alongside any other actors. He didn't particularly enjoy the experience.
Though never mentioned in the film, it is revealed by the directors in the commentary that Crush and his crew of thrill-seeking turtles are headed for Hawaii. Also mentioned in the commentary is that the young turtles' shells are modeled after Hawaiian shirts.
Demand for tropical fish exploded right after the film's release, especially for clown fish and blue tang, the main characters' species. And just like Darla, many new pet buyers had no idea how to take care of their pets and ended up killing them. It was later revealed that saltwater tropical fish need a 30-gallon aquarium with carefully controlled salinity levels, as anything less will kill them. The rise in demand took fish importers by surprise and the population of clown fish dropped by 75 percent in some areas. Although this isn't the first time something like this happened, Finding Nemo was different because this time, the whole premise of the movie was freeing the animal from being a pet. Then again, pet owners who took that premise to heart did not respond much better. Some released their venomous fish into the ocean, ruining Florida's ecological balance. Others flushed fish down the toilet to free them and these fish died before even reaching the sewers.
SERIES TRADEMARK: Among the toys in the waiting room are the jack-in-the-box and Buzz Lightyear and, on a shelf, the plane he used to "fly" in Toy Story (1995) and Pixar's trademark ball from Luxo Jr. (1986).
Per the DVD extras, Albert Brooks spent an entire day in the recording studio improvising badly mangled versions of the anemone joke; no two tellings were fumbled in the same way. He had the recording technicians in stitches for the duration.
SERIES TRADEMARK: The dentist's camera's model number is A-113, a number which appears in all Pixar movies as a reference to the California Arts University room, where the animators of Pixar Studios attend.
Megan Mullally revealed that she was originally doing a voice in the film. According to Mullally, the producers were quite disappointed to learn that the voice of her character Karen Walker on the television show Will & Grace (1998) wasn't her natural speaking voice. The producers hired her anyway, and then strongly encouraged her to use her Karen Walker voice for the role. When Mullally refused, she was fired.
According to the DVD, the names of the nine boats seen in the Sydney harbor are: Sea Monkey, Major Plot Point, Bow Movement, iBoat (a reference to iTunes by Apple, the company created by Pixar CEO Steve Jobs), Knottie Buoy, For the Birds (2000), Pier Pressure, Skiff-A-Dee-Doo-Dah (a reference to Song of the South (1946)'s most famous song "Zip-a-Dee-Doo-Dah"), and The Surly Mermaid.
In the original cut of the movie, the whale that swallows Marlin and Dory approaches them from the front. This version of the scene appeared in an early trailer. The final version, with the whale coming from behind, was inspired by an early animation test showing a whale emerging from the murk of the ocean behind a small fish.
Most of the fish are actual saltwater fish that can be found in the pacific ocean. Nemo is a clownfish (so is Marlin), Dory is a Regal Blue Tang, Gil is a Moorish Idol, Bloat is a Porcupine Puffer Fish, Bubbles is a Yellow Tang, Peach is an Ochre Starfish, Gurgle is a Royal Gramma, Jacques is a Cleaner Shrimp, and Deb is a Damsel Fish.
According to the DVD, there are some references to Massachusetts in the film as one of the creators is from Rockport, Massachussetts. While various sea creatures are relating Marlin's quest across the ocean, one step is a group of lobsters that speak with Boston accents and slang ("wicked daahhk").
Two experiences in Andrew Stanton's life shaped the film. The first one was recalling trips to the dentist as a child and being fascinated by the aquarium there, the second was realizing that he was naturally over-protective of his young son.
Last of the 3 Consecutive Pixar Films to have Lee Unkrich as the Co-Director. He wouldn't be able to direct another Pixar Film until Toy Story 3 (2010)_ and Coco (2017) 7 and 14 years later respectively as the Main Director.
The scene were Nigel evades a group of seagulls by narrowly passing between the mast and mainsail of a yacht recalls a similar scene in Star Wars: Episode V - The Empire Strikes Back (1980). In that movie, Harrison Ford's character Han Solo flies his ship, the Millennium Falcon, through a narrow canyon in order to evade the pursuit of a group of TIE fighters. In both instances, the hero, at the last instant, rolls 90° and flies through the opening, while his pursuers hit the surrounding walls (or sails in the case of the seagulls).
The trivia items below may give away important plot points.
Afraid that kids would try releasing their pet fish by flushing them down a drain, a company that manufactures equipment used by water filtration and sewage treatment plants released a warning the Thursday after the film came out, saying that, even though drains do eventually reach the ocean, before it got there, the water would go through equipment, which breaks down solids, and went on to say that in real life, the movie would more appropriately be called "Grinding Nemo."
The pre-end credit scene show all the aquarium fish from the dentist's office are free and out of their plastic bags. As the closing credits are about to end, there was a short segment where the angler fish swims up to the tiny green fish and the tiny fish opens its mouth and swallows the angler fish.
The first Pixar Film to show blood (not counting A Bug's Life (1998) where it was only a sample as opposed to someone bleeding from an injury), as well as the only G Rated Film of Pixar's to have it shown. It was shown where Dory got hit in the face by a scuba mask when she was trying to show it to the sharks and read what the mask says, but Marlin refuses to have the mask be shown and he pulls it but Dory pulls back, and Marlin accidentally gave Dory a nosebleed after letting go of the mask.