Science Kids Fastest Animals On Earth - Cheetah, Pronghorn, Springbok, Quarter Horse and More! The most surprising fact about fast animals from the video is the debate over whether the black Marlin or sailfish holds the title for the fastest fish in the ocean. Despite the black Marlin's record-breaking speed of 82 mph, some question the validity of this speed based on typical sightings. Additionally, the black Marlin's large size and migratory behavior add to its mystique as a powerful and impressive ocean predator.