Jim Hill reveals that the great white shark Glut, seen briefly in Ariel's introductory scene in The Little Mermaid, was originally meant to have a much larger role: "in his desperate desire to consume Ariel & Flounder as he surges through the ship, the shark [would have swallowed] a lot of things. Including a French horn. Then the two friends escape only because Glut gets his head caught in the rope end of an anchor." Much later on, when Ariel and Flounder swim to reach the wedding barge, Glut would have spied them again, out in the open ocean. "So the Great White swims up underneath them and throws open his enormous jaws when... Ariel & Flounder reach the boat. The Little Mermaid is able to clamber up the side of the ship just as Flounder spies Glut. The terrified little fish then crams the barrel into the Great White’s gaping maw. As Glut bites down on the wooden container, the camera zooms in to reveal the 'Gun Powder' label that’s pasted to the side of the barrel. Cut to the deck of the wedding barge. Prince Eric & Ursula’s ceremony is interrupted as the ship is rocked by an enormous off-screen explosion. Tons of water now rain down on everyone standing on deck. After a slight pause, a battered French horn falls out of the sky--landing right at Ursula’s feet. Time and money played an important part in Glut’s return getting cut."

In the late 1930's, Walt Disney toyed with several Hans Christian Andersen stories as the subject for feature films, as well as a large-scale film biography of the storyteller, to be made in live-action, with the stories as animated segments. This ambitious project was developed at length as a collaboration with producer Samuel Goldwyn (who had registered the tide Hans Christian Andersen and commissioned several screenplays). Illustrator Kay Neilsen, who had been influential in the design of the "Night on Bald Mountain" sequence of Fantasia (1940), prepared a number of striking story sketches in pastels and watercolor, both for the live-action and story sequences, including The Little Mermaid.

Although the Disney/Goldwyn project was never made (Goldwyn made a live-action musical of Hans Christian Andersen in 1952), artists researching for The Little Mermaid in 1986 discovered Neilsen's art from the 1930's, which held such inspiration for them that they gave Neilsen a screen credit for visual development nearly fifty years after Neilsen had completed the work!

Some of the other visual inspirations for the film were cartoonist Rowland B. Wilson, illustrator and author Chris Van Allsburg and veteran Disney layout man Ken O'Connor.

The Little Mermaid is also a special animation effects tour de force, almost eighty percent of the film required some kind of effects animation-billowing sails, schools of fish, shadows, fire, fog, explosions, surface reflections, underwater distortions, ripples, bubbles and two storms at sea.