Nemo is Francine Frensky's pet cat.
Oliver Frensky found him in an Elwood City Dump landfill in which he worked which led to the adoption of Nemo. Initially, Catherine had adopted him as her own pet, naming him Rose Petal, but later, she realized that he was more suitable as Francine's pet, leading him to be renamed Nemo.
Like Pal, in some episodes he is shown to be able to communicate with other pets, babies, and toys. He is usually cast as an antagonist in these situations. During these interactions, especially with Pal, he is prone to insults and sarcasm, but can occasionally be helpful.
- Nemo's appearance has changed since his debut. His head and eyes became more oval shaped and he now has less black fur.
- Nemo was friends with Pal in "Francine and the Feline", but they have since become mortal enemies. One exception is in the episode, "Pet Projects", when their owners and friends were putting embarrassment in the camera films starring them. They formed an alliance to get revenge after the humans did the films for their own sake.
- On the front cover of Arthur's Pet Follies on VHS and DVD, Nemo's original design was used.
- Nemo often calls Pal "dog" or "puppy".
- According to Francine in "What is that Thing?", Nemo was named after "Captain Nemo" from the Jules Vernes novel Twenty Thousand Leagues Under the Sea.
- Much like Jenna Morgan, Nemo is lactose intolerant, as seen in "Pet Peeved".
- Since Nemo was found in the city dump it could be possible that he is a feral cat.
- Nemo is a tuxedo cat and a Domestic short hair.
- He also calls Killer a "little fuzzy rat", as heard from "It Came From Beyond".
- In "Pets and Pests", Nemo states that he has a big family with fifteen brothers and sisters. When he was a kitten, he always got left behind, presumably because he was the runt of the litter.
- Francine and the Feline
- What is that Thing?
- Pet Peeved
- The Secret Life of Dogs and Babies
- It Came From Beyond
- Feeling Flush
- Baby Kate and the Imaginary Mystery
- The Great MacGrady
- Around the World in 11 Minutes
- Muffy and the Big Bad Blog
- Mei Lin Takes a Stand
- Pet Projects
- Pets and Pests (final speaking appearance)
- The Last Day
- The Master Builders
- See: Nemo/Gallery