This tale takes place underwater with the fish Marlin (voiced by Albert Brooks), whose spouse and baby fish eggs get eaten by a vicious shark in the beginning. Years later Nemo (voiced by Alexander Gould, Elliot's son?) is a bit older, and heading off to fish school for the first time.But haunted by the fact that his spouse and offspring were all killed years ago, Marlin is extremely over-protective of his one remaining family member.
In "Monsters, Inc.," they showed us the monster world.
There are a few things that one can always expect from Pixar films: They can expect something (such as toys) to be given their own world.