Hank has only seven tentacles because the animators realized they could not fit eight onto his body. His backstory was rewritten to account for the missing limb. For similar reasons, in the classic sci-fi film Le monstre vient de la mer (1955) special effects genius Ray Harryhausen was only able to create a stop-motion giant octopus with six tentacles.
Hayden Rolence replaces Alexander Gould as the voice of Nemo, due to Gould having outgrown his original role since Le Monde de Nemo (2003), though Gould does have a cameo as Passenger Carl. Bennett Dammann replaced Nicholas Bird as the voice of Squirt for a similar reason.
The license plate on the truck is CALA113. "A113" appears in all Pixar movies, as a reference to the Cal Arts room where many of the animators of Pixar Studios attended.
The setting of the film was changed from an aquatic park to a Marine Biology Institute after the controversial documentary Blackfish (2013) was screened for the crew of Pixar.
The Pizza Planet truck, a truck that is used to make delivery for "Pizza Planet" in Toy Story (1995), appears in a wrecked sunken state at the area where Dory, Marlin, and Nemo encounter the giant squid, as well as on the freeway, passing by the truck heading to Cleveland.