When Don Lino is clearly seen for the first time (when he looks up from the aquarium), a mole can be seen near his right eye - a distinct facial feature of Lino's voice actor Robert De Niro.
During the end credits, Crazy Joe the hermit crab taps on Head of Artistic Development Frank Gladstone's name and yells out "What! You see this guy? He hardly worked on the movie at all! Always on the phone yakking yakking yakking...".
In the film's early stages of production, James Gandolfini was considered for the voice of Don Lino, Christopher Walken was considered for the voice of Luca the Octopus and Sacha Baron Cohen was considered for one of the Jellyfish.
In the racetrack sequence, there are more than 16,000 computer animated 3D characters in the stands.
When Oscar goes to the time clock, there's a note on the wall saying "If you don't come in Saturday, don't bother..." A reference to a famous memo Jeffrey Katzenberg sent to execs while he was with Disney.
There are nods throughout the movie that sharks's den is the wreck of the Titanic. Yet, the outside and interiors of the shipwreck are based on the SS Normandie, a French ocean liner of the 30's. Particular examples are the scenes at the bar when Lino and Sykes meet for the first time and the dining room where the sitting is set.
A sequel has been discussed, but never produced.
Some of the 'fishified' products are "Coral Cola", "Gup", "Fish King", "Old Wavy" and "Newsreef".
While Lenny is a self-confessed vegetarian, he eats his best friends Oscar and Angie (although temporarily).
The shark gangster voiced by Peter Falk was originally called Don Brizzi. Bowing to pressure from the Italic Institute of America, an organization protesting Hollywood's stereotyping of Italians as mobsters and gangsters, Dreamworks agreed to change the name of the character to Don Feinberg just before release.
Anthony Anderson was cast as a sperm whale, but the role's suggestive dialogue got his character cut down. Anderson has only a few non-risqué lines: when the whale meets Angie, and when Oscar cleans the whale's eye.
Some of the actors - notably Robert De Niro and Martin Scorsese, Will Smith and Jack Black, and Smith and Renée Zellweger - recorded their lines together.
The plot has some resemblance to "The Reluctant Dragon," a short story from 1897 written by Kenneth Grahame.
Ernie the Jellyfish (Ziggy Marley) sings the song "Three Little Birds" - a song written by Ziggy's father, Bob Marley, with the small difference of Ziggy changing "birds" to "fishes" in keeping with the film's aquatic theme.
LOGO GIMMICK: The fisher boy in the moon throws his line (worm attached) into the ocean, where the worm encounters Lenny.