Two ocellaris clownfish, Marlin and his wife Coral, admire their new home in the Great Barrier Reef and their clutch of eggs when a barracuda attacks, knocking Marlin unconscious. He wakes up to find that Coral and all but one of the eggs have disappeared. Marlin names this last egg Nemo, a name that Coral liked.
Nemo develops a smaller right fin as a result of damage to his egg during the attack, which limits his swimming ability. Worried about Nemo's safety, Marlin embarrasses Nemo during a school field trip. Nemo sneaks away from the reef and is captured by scuba divers. As the boat departs, a diver accidentally knocks his diving mask overboard. While attempting to save Nemo, Marlin meets Dory, a good-hearted and optimistic regal blue tang with short-term memory loss. Marlin and Dory meet three sharks