Exploring the Reef (2003)
Exploring the Reef (2003) is a humorous short documentary film included on the second disc of the Finding Nemo DVD. It also appeared at the end of the VHS of Finding Nemo. It features Jean-Michel Cousteau in a documentary film he is trying to make about coral reefs, but Marlin, Dory, and Nemo keep interrupting him.
More at Wikipedia.