Flounder is a character in the movie "The Little Mermaid" and is a bright yellow and blue colored tropical fish. Despite the name, he is not a flounder. According to a marine biologist, Flounder is an Atlantic sergeant major. However, there appears to be some debate about his species. Some have guessed that he may be some sort of angelfish or a colored reef fish. In the animated TV series, Flounder was confirmed to be a guppy fish.