They suggest that Nemo was actually dead from the beginning of the film, suggesting that Marlin's entire family, including Nemo's mom, Nemo, and all of their other children, were killed by the fish — Meaning there were no survivors.

Is Nemo just Marlin's imagination?

It's actually Marlin's imagination because he's grieving over the death of his wife and all his kids. "And to make everything worse, the word Nemo in Latin means no one. "Disney's literally telling the audience we have a movie called Finding Nemo but it actually means finding no one, because Nemo's not real."

Did Nemo really exist in the movie?

He names his only son Nemo; Nemo in Latin translates to 'no-one' or 'nobody'. It gets weirder. “So, Nemo doesn't actually exist, the entire movie is about Marlin going through the five stages of grief.”