Nemo is the titular tritagonist of Finding Nemo and the tetartagonist of its sequel, Finding Dory. He is a clown fish who got kidnapped by scuba divers but then many days later was freed by a fish named Gill and reunited with his father Marlin.
He was voiced by Alexander Gould in the first film and Hayden Rolence in the sequel.
When Nemo was still an egg, his mother Coral and the eggs of his brothers and sisters were eaten by a barracuda. Nemo survived this with his egg getting slightly damaged and was found by his father Marlin.
First Day of School and Kidnapped
Six years later, Nemo is now a mischievous clownfish with a small right fin due to the egg damage from the barracuda attack and wants to have school. After waking Marlin, the two fish go to school and meet the young sea creatures. He goes to school with Mr. Ray and later meets three classmates (Tad, Sheldon, and Pearl) who go to open water after being bored. Marlin warned him that he is too young to go to open water, and Nemo retaliated by pointing out his father's cowardly side, unaware that Marlin was overprotective on him out of trauma due to Coral's death.
After feeling embarrassed, the angered Nemo swims out into open water to touch a nearby boat, against Marlin's warning which only provokes him instead. With everyone being close to the open sea for too long, they attract the attention of 2 divers who approach them. In the chaos, Nemo gets captured by one of the divers, who is later revealed to be a dentist named Phillip Sherman, and is kept in his aquarium where he met the Tank Gang and the pelican Nigel.
The Tank Gang help him try to do the escape plan where as stated by Gill, his small size allowed him to slither through the tube in the aquarium as a means to sabotage the aquarium's filter. The first attempt ended in failure, but after hearing the news about the adventures that Marlin has gone through from Nigel, Nemo started out the second attempt which proved to be successful. Unfortunately, on the scheduled day for escape that was arranged by the Tank Gang, Sherman has installed a new device that would render their recent escape plan failed unless they destroyed it too.
Reunion and Saving Dory
When Marlin and Dory get help from Nigel, the plan failed due to Marlin's desperation winding up ensuing chaos that forced Nigel to retreat. When Nemo gets carried in a bag (making Marlin think he's dead), he is later grabbed by Phillip's niece Darla and then shook. The Tank Gang's leader Gill stops her and then catapults Nemo into the spit drain. It leads him back to the ocean and where he later is lost with the sewer crabs.
When Marlin and Dory find Nemo, they are lost with the groupers being caught by the fishermen. Nemo later gets in the net to free Dory in order for all the groupers to swim faster to free themselves. After that, Nemo is seen injured from the fallen net. Marlin uses his flashback and brings Nemo back to their home. After that, Nemo has a life that he will never misbehave with Marlin and goes to school with Tad, Sheldon, Pearl and a new classmate, Squirt, who is the son of Crush, a turtle Marlin and Dory befriended.
Nemo reappears in the sequel with Hayden Rolence doing the part, since Alexander Gould's voice deepened too much for him to reprise the role. He helps his father find Dory's parents in the film and is obviously more determined than Marlin in doing so, though the effort to help her turned out to not be as easy as it seemed.