Flying fish are marine oceanic fishes of the family Exocoetidae. They are about 50 species, and they live worldwide in warm waters. They are noted for their ability to glide. They are all small, with a maximum length of about 45 cm (18 inches), and have winglike, rigid fins and an unevenly forked tail.
They do not fly actively: their fins do not flap. What they do is speed towards the surface and keep on going. When they leave the water they glide, sometimes for a surprising distance. It is generally thought to be an adaptation which helps them escape predators.