Dory

Dory is the deuteragonist of Finding Nemo and the titular protagonist of Finding Dory. She is a blue-tang fish who suffers from short-term memory loss.

Biography
"Throughout the vast ocean you will not find a fish more hospitable, more friendly, and more sociable than Dory. She would love to chat with you all day and tell you her life story... but she can't. Dory suffers from short term memory loss. Dory is the aquatic Good Samaritan who offers to help Marlin on his journey to find his son. She is certainly an odd partner for such a quest, but her optimism proves an invaluable quality to help overcome the impossible. To Dory, the glass is always half-full."

Finding Nemo
She helps Marlin on his journey to rescue Nemo while heading to Sydney. She suffers from short-term memory-loss.

The friendly female can read and is very happy to have a companion. Marlin takes advantage of her short attention-span, but he later regrets it when it physically hurts her.

Dory never remembers Nemo's name. However, she does seem to care about the little fish.

Additionally, Dory comforts everybody she sees, like in the movie. The words: "There, there. It's all right. It'll be okay," are used by Dory twice in the movie. Once when she first met Marlin, because she thought his head was hurting and again in the whale when Marlin was worried about Nemo. That being said, nearly at the end of the movie, after Nigel puts Marlin and Dory back in the ocean, a depressed Marlin barely kept his distance from Dory when she swam to him. After Dory tried so hard to comfort him, Marlin suggested that if Dory never took care of him along the way, he never would have even made it to Sydney.

Despite her sunny outlook and demeanour, there is some tragedy to Dory. Because of her short term memory loss, there's no telling how many life experiences have eluded her, or how many loved ones she lost that she couldn't remember. When she starts travelling with Marlin, her memory starts improving, as indicated when she can repeat the address "P. Sherman, 42 Wallaby Way, Sydney". When Marlin thinks that Nemo is dead, and starts to go home, Dory doesn't want him to leave, because she is afraid that if she can no longer see him, then she'll forget everything. This fear is founded, as when the hopeless Marlin leaves her, not a few minutes afterwards her entire adventure has been (temporarily) wiped clean from her mind.

After Marlin leaves Dory meets Nemo who had escaped alive and at first she doesn't remember him but when she sees the word Sydney again all her memory comes back and she takes Nemo to his father. After finding help from some crabs although only by blackmail of feeding them to seagulls, Dory and Nemo find Marlin, resulting in a happy reunion between Nemo and Marlin that is cut short when Dory gets trapped with a school of fish in a fisherman's net. Nemo rushes to help a distressed Dory, they tell the other fish to swim down together, and they all manage to escape the net.

At the conclusion of the film, Dory is seen to have become Nemo's adoptive mother and a latest member of Bruce's Fish are Friends Club as Bruce, Anchor, and Chum come over to drop Dory off.

Finding Dory
Dory returns in the sequel Finding Dory. In this film, it is discovered that Dory was born in the "Jewel of Morro Bay" (The Marine Life Institute) in California. Whilst on a day trip to a stingray migration, the word "undertow" sets off a flashback to her time in the institute. This forces her, Nemo and a reluctant Marlin to travel across the ocean, with the help of the turtles from the first film. Upon arriving in California, the trio swim around a sunken cargo ship, with Dory shouting, "Mom! Dad!" The crabs shush Dory, and this sets off another flashback, revealing her parents' names. She now shouts these until she awakens a giant squid. The said squid nearly eats Nemo, this leads to Marlin sending Dory away. In search of 'help', she hears the narration of Sigourney Weaver. It makes her go -- with her head sticking out -- to the surface of the ocean. She is taken by some marine life institute workers, who place her in quarantine. She is given a tag that transfers her to a permanent aquarium in Cleveland. Hank, an octopus (with 7 tentacles), has traumatizing memories of the ocean so he's desperate not to be released back to the ocean. In exchange for the tag, he offers to take her to her parents.

Hank takes Dory to a map of the institute so she can figure out where her parents are. Whilst looking at the map, she remembers that her mom loved shells, especially purple shells. Whilst escaping some humans, Dory ends up in a bucket of dead fish for Destiny, the whale shark to eat. It's revealed that she was Dory's pipe pal during childhood and that's how she could speak whale in "Finding Nemo". We are also introduced to Bailey, a beluga whose echolocation is faulty. Dory learns she is from the Open Ocean Exhibit and is offered a route through the pipes. However, due to her memory loss, she didn't trust herself to get there. Therefore, Hank unwillingly wheels her around in a stroller, with Dory being distracted by a sign about 'the world's strongest pair of glasses'. This causes Hank to snap at Dory, and during the argument the stroller rolls into the kids zone and they end up in a touch tank. A mini horror movie occurs, as the marine life desperately try to avoid being touched. Dory "just keeps swimming", revealed in a flashback to when parents taught her that song.

Whilst escaping, Hank gets poked, excretes ink and this makes all of the children leave. Hank climbs up above the top of the Open Ocean Exhibit and lowers Dory in, wishing her luck. She eventually uncovers her childhood home, and after seeing a shell, she remembers what separated her from her parents. After seeing her mother cry, she tried to get her a purple shell, as 'mommy loves purple shells'. However, the strong undertow current pulled baby Dory through the pipes and out into the sea. After this revelation, two small crabs tell Dory that the Blue Tangs are in Quarantine. Dory is forced through the pipes, before she eventually gets lost within them. She call out to Destiny, and Bailey uses his echolocation. However, a miscommunication between them leads to Dory bumping into Marlin and Nemo. Whilst swimming through the pipes, Marlin finally discloses that he is truly thankful for Dory and everything she's done. Without her, he would never have found Nemo in first film. Eventually, the trio end up in quarantine.

After jumping from tank to tank, they reach the blue tang tank. It is discovered that Dory's parents went to quarantine after she disappeared and were presumed dead. Dory, heartbroken is taken out the tank by Hank, who accidentally left Marlin and Nemo in the tank. Hank is taken by a worker, he drops Dory and she ends up in a drain and back in the kelp forest from near the start of the film. She struggles to remember what's happening, then sees a shell. She follows the shells like she did as a child. She reaches a cave, before turning around and reuniting with her parents. She suddenly remembers Nemo and Marlin, and attempts to rescue them. She goes back to the institute, breaks out Destiny and Bailey and they chase the truck towards a bridge. Dory sends otters up to the road, resulting in traffic stopping. An otter carries Dory to the truck, and Hank places her in a tank.

Marlin signals Becky and she takes Marlin and Nemo, leaving Dory behind. Marlin orders Becky to get Dory but before they get out, the door is locked. Hank and Dory escape from the truck and somehow manage to hijack it. Hank drives the truck, with Dory giving him directions. She follows the seagulls back towards the beach, and reaches the bridge where police had blocked it off. Dory yells Hank to drive it into the ocean, releasing all of the fish back into the ocean. Dory's parents leave as a family with her, Nemo and Marlin. Hank becomes a substitute teacher for Mr. Ray (who migrated) and Bailey and Destiny are assistants. Dory and Marlin swim to look at the view of the drop-off, happy that both of them had managed to find their family.

Trivia

 * According to director Andrew Stanton on the audio commentary for the Finding Nemo DVD, in the original story Dory was going to be a male character but when Stanton went home to write the script his wife was watching The Ellen DeGeneres Show and when he heard DeGeneres' voice he decided to change Dory to a female and cast her in the role to which she accepted.
 * Dory has made cameos in several of Boom! Studios' Disney comics including The Incredibles, where she appears in an underwater scene, and Darkwing Duck (on the last page of issue 7), where she and other Disney sea creatures react in fear to the return of the villainous Paddywhack.
 * On the Disney website, they mistakenly refer to Dory as a Yellowtail Tang. Although she does have a yellow tail, she is a blue tang, this is a different species of fish.
 * The nicknames Dory gave to Nemo (in order of appearance) are Chico, Fabio, Bingo, Harpo, and Elmo. The first four are a reference to the Marx Brothers (excluding Groucho), while the fifth is a reference to the red Muppet monster from the children's puppet show Sesame Street.
 * Many people think that goldfish have poor short term memories. Even though she's not a goldfish, this point might be linked to her amnesia-like condition.
 * In Finding Nemo: The Musical, Dory wears mismatched socks.
 * The toy swimming fish which Dory and Marlin meet in the tank outside the Institute Gift Shop resembles a blue tang with the primaries swapped around, so that it has a green body and a magenta tail.