However, depending on what you consider a "Little Mermaid" movie, there are a few options:
* The Little Mermaid: Ariel's Beginning (2008): This is a prequel film that tells the story of Ariel's childhood and how she became fascinated with the human world.
* The Little Mermaid II: Return to the Sea (2000): This is a sequel to the original film that follows Ariel's daughter, Melody, and her adventures.
* The Little Mermaid: Ariel's Beginning (2008): This is another prequel film that focuses on Ariel's relationship with her father, King Triton.
It's also worth noting that a live-action remake of The Little Mermaid was released in 2023, starring Halle Bailey as Ariel.
So, depending on your definition of "fourth Little Mermaid," the answer could be any of these films or even the live-action remake.