Andrew Stanton’s Finding Nemo is one of the most beautiful animated movies ever made, both in its gorgeous nautical imagery and in its powerful emotional resonance. The story of an overprotective father’s search for his missing son connected with audiences across the world who fell in love with Marlin and Dory, and followed them on an incredible adventure.

It wasn’t an easy movie to make. From the story stage to the final rendering, Finding Nemo was a tough nut to crack. Pixar broke new ground to animate the ocean, while casting Marlin proved to be a difficult task. So, here are 10 interesting facts from the making of Finding Nemo.

Inspiration For The Movie Began With Andrew Stanton’s Childhood Trips To The Dentist’s Office

The early inspiration for what would eventually become Finding Nemo began with director Andrew Stanton’s childhood trips to the dentist’s office. He used to assume that the fish in the fish tank came from the ocean and wanted to go home.

He realized the undersea world would make a great setting for a computer-animated film during a trip to Six Flags Discovery Kingdom (which, at the time, was called Marine World). Then, when he became a father, he realized he was naturally overprotective of his son. All these elements swirled together in his head to create Finding Nemo.

William H. Macy Was Initially Cast As Marlin

William H. Macy was the first actor to be cast in the role of Marlin. He even recorded all of his lines and the animators animated Marlin’s lips to match his line delivery. But when the Pixar creative team screened the film, they found that Macy’s delivery was so dramatic that it sucked all the comedy out of the movie.

So, the role was recast with Albert Brooks to capture Marlin’s constantly panicking state, and according to director Andrew Stanton, Brooks’ performance saved the movie.

In The Original Story, Marlin’s Backstory Was Revealed Gradually Through Flashbacks

In the original story outlines for Finding Nemo, Marlin’s backstory — the death of his wife Coral and all of his other babies at the jaws of a bloodthirsty barracuda — was going to be doled out slowly throughout the movie in a series of flashbacks.

However, in the first few screenings, Marlin came off as way too overprotective and panicky because the audience didn’t know what he’d been through to make him that way. So, Andrew Stanton moved the whole backstory up to the movie’s opening and gave us the devastating prologue that Milhouse’s parents skip on DVD viewings.

Michael Eisner Expected Finding Nemo To Be Pixar’s First Box Office Bomb

Disney CEO Michael Eisner always had a contentious relationship with Pixar and particularly its owner, Steve Jobs. When he saw an early cut of Finding Nemo, Eisner told the Mouse House’s board of directors that he was sure it would be Pixar’s first box office bomb. Eisner was left with egg on his face when it surpassed The Lion King to become the highest grossing animated movie of all time and also went on to become the best-selling DVD ever.

Even worse for Eisner, Pixar’s contract with Disney had almost expired, and Jobs gave Eisner a tough time in the re-negotiation. This was one of many factors that led the shareholders to fire Eisner as CEO. Pixar wouldn’t have a box office bomb for another 12 years, when The Good Dinosaur failed to make a financial splash.

Megan Mullally Was Fired Because She Refused To Play Her Character With A Karen Walker Voice

In the years since Finding Nemo hit theaters, Megan Mullally has revealed that she was offered a role in the film. However, when she came in to record her lines, the Pixar team was disappointed that Karen Walker’s voice from Will & Grace is not her normal speaking voice.

They pretty much wanted a fish version of Karen Walker, so they asked her to play her Finding Nemo role in Karen’s voice. When she refused to do so, they fired her.

Each Frame Took Up To Four Days To Render

Each frame of Finding Nemo had a resolution of 1600 x 900 and made up 1/24th of a second of the finished movie.

Due to the complexity of animating underwater environments with sunlight shining through the surface and reflecting on the fishes’ scales, each of these frames took up to four days to render.

Dory Was Originally Written As Male

Andrew Stanton originally wrote the role of Dory as male. However, while he was writing, he had an episode of Ellen DeGeneres’ sitcom Ellen playing in the background.

DeGeneres changed the subject she was talking about five times in the space of a few minutes and Stanton realized she’d be perfect for the character, so he changed the character to female with DeGeneres specifically in mind.

Albert Brooks Was Disappointed He Didn’t Get To Bounce Off The Other Actors

Albert Brooks has famously played a few guest roles on The Simpsons, and he enjoyed recording his lines with the other voice actors and bouncing off of them to ad-lib dialogue in the studio. So, he was a little disappointed to find that he had to record his lines for Finding Nemo on his own. It would’ve been great to have some improvised riffs between Brooks and Ellen DeGeneres in the movie.

Brooks still had fun with the role. He spent an entire day of recording improvising botched versions of the anemone joke. He didn’t bungle the joke the same way twice, and he kept the audio technicians laughing all day.

The Animation Of The Ocean Was Surprisingly Deemed Too Realistic

Getting the look of the undersea world right was key to the success of Finding Nemo, so the animators were sent to aquariums and on oceanic dives in Monterey and Hawaii. They were also given lectures by an ichthyologist and study sessions in front of the 25-gallon fish tank in Pixar’s production office.

When the animators first created the surface of the ocean, it was actually deemed too realistic, and were told to make it look more artificial so that audiences wouldn’t think it was actual live-action footage of the ocean.

Ellen DeGeneres Nailed The Most Emotional Scene In One Take

When Andrew Stanton first cast Ellen DeGeneres as Dory, the producers worried that, as a comedian and not an actor, DeGeneres wouldn’t be able to elicit the right emotions for the scene in which Dory begs Marlin not to leave her. However, when it came to recording that scene, those worries turned out to be unfounded.

The producers originally told DeGeneres to record a trial run of the scene, go home with the audio, and work on it overnight. Her first take of the so-called trial run ended up being so powerful and heartfelt that the producers used it in the film.