Some species of fish, such as the moray eel, can swim backwards. Species of fish that do not swim horizontally include the catfish, the sea horse and the shrimp fish, who swim vertically.
The style of swimming that permits backward movement is called anguilliform locomotion and uses undulatory movements. A fish employs several swimming styles depending on their environment. Flying fish evolved to glide above the water by flapping their fins. Most species of fish are color-blind, and some species can live 50 years or more. Porcupine fish inflate themselves by pumping water into special pockets in their body when in the sea or by pumping air into the pockets when they are above the surface. A fish breathes by taking in oxygen from the surrounding water.