According to Hans Zimmer, he asked producer Jeffrey Katzenberg that he couldn't deal with any more epic films, but wanted to do a fun animated movie instead, and so got the chance to compose for this film.
The original title was "Sharkslayer", but it was changed to "Shark Tale" about a year before release because Jeffrey Katzenberg thought the title might scare families away (the title still appears in some early promotional material). The change is clear in the movie, as in the song before the credits, the singers interlock between calling the movie "Sharkslayer" and "Shark Tale".
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.
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.
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.
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.
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.
Classifying the characters in terms of species, Oscar is a bluestreak cleaner wrasse (which explains his whale-cleaning status), Angie is a marine angelfish, Sykes is a porcupinefish, Lola is a lionfish, Don Feiberg is a leopard shark, and Crazy Joe is a hermit crab.
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...".
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.