Finding Nemo is a 2003 animated Pixar film with talking fish. It is about a young clownfish named Nemo who is captured by scuba divers when he disobeys his father Marlin and gets defiantly close to a speedboat, outside the protection of the reef. When Nemo was still an egg, Marlin lost his wife (and Nemo's mother) Coral and all of the other eggs in an attack from a fearsome barracuda. So Marlin is understandably overprotective. Finding Nemo is the highest-grossing G-rated film of all time, and one of the most popular quotes from the movie is the phrase "just keep swimming."

On the surface, this is a cute and catchy thing a fish might say, but after the conclusion of the film, it takes on a different meaning. Some fans of the now-classic animated film think Marlin and Dory might have more in common than first thought, and they may both be suffering from mental illness of some kind. Dory suffers from acute short-term memory loss (a trait that is hereditary), and some fans think Marlin is suffering from grief and post-traumatic stress disorder.

RELATED: Pulp Fiction: What Was In That Briefcase?

One theory states that Nemo does not actually exist, and Marlin is just in the denial stage of grief—where his entire family has just been brutally slaughtered. In the theory, Marlin has been hiding from the barracuda, but then realizes and simultaneously denies what just happened. Marlin frantically looks for any surviving eggs, and because there are none and he is too desperate for some good news, his mind creates "Nemo"—the last surviving egg that grows up to be a little impaired from either genetics or the attack.

On Nemo's first day of school, Marlin has a mental breakdown because when he goes to take his imaginary child to the teacher Mr. Ray, the teacher tries to tell him the truth, and Marlin's fight or flight kicks in, and he ventures out into the ocean looking for Nemo, whom he subconsciously knows to not exist. Perhaps Nemo represents Marlin's will to "just keep swimming" and when he runs away after a panic attack, Marlin has to find his son Nemo—or his will to keep living. Dory is always forgetting everything, so she doesn't find anything suspicious about Marlin or his imaginary son Nemo. Marlin and Dory were there for each other in the theory and helped each other out in a time of need.

Another more believable theory is that Marlin is overprotective still because of his desire to protect his only remaining son and actually does suffer from some PTSD. Nemo has also inherited some of the anxiety from his father due to his constant worrying, and Nemo is a representation of those with deformities. In this second theory, Finding Nemo is really just a fun story and way to deliver a more powerful message to a young audience about the effects of untreated mental illness, and the benefits of seeking help and guidance.

Other characters in the film, like Jacques and Gurgle from the dentist's office fish tank, are representations of obsessive-compulsive disorder because of their need for cleanliness—or control. Another fish from that tank, Deb, sees her reflection in the fish tank and views it as her "sister" who is always in tune with her. This could be seen as dissociative identity disorder. The sharks Bruce, Chum, and Anchor are shown in some kind of AA meeting for their addiction to eating fish where they claim "fish are friends, not food."

Finding Nemo

Perhaps another message of Finding Nemo is to overcome challenges and look past each other's differences and be kind to one another no matter how we look or what we're going through. The last theory is a more fun theory, kind of like Finding Nemo meets The Shining. When confined to small spaces, clownfish are known to be aggressive and will attack and kill one another. Eggs will decay if not fertilized properly, so clownfish will eat their own eggs if this starts happening. Perhaps Marlin was paranoid about the outside world, so he stayed hidden at home. Confined to the small space, he killed his wife. Desperate for food, he ate all of the eggs.

Two possibilities are that Marlin ate all but one of the eggs before coming to his senses, or that he ate them all and then had his mental breakdown similar to the first theory. Finding Nemo is a highly entertaining movie to watch for those of all ages, but it might be more fun as an adult to give the movie a watch while testing out these theories. Although there are a lot of plot holes in each of these theories, it is still fun to imagine a dark, secretive meaning behind an otherwise innocent movie.

MORE: The Tim Burton Theory: Is It All Just One Giant Movie?