Waterbending, one of the four elemental bending arts, is the hydrokinetic ability to control water in all of its various forms. This type of bending is used by the people of the Water Tribe, who are divided into the Southern, Northern, and lesser-known Foggy Swamp tribes, as well as those of the United Republic, each with their own unique bending style.
Water is the element of change. The moon is the source of power in Waterbending, and the original Waterbenders learned to bend by observing how the moon pushed and pulled the tides. The Water Tribes are the only people who did not learn to bend from an animal, though the Moon and Ocean Spirits took the form of koi fish in the mortal world near the beginning of the Avatar world.