Infant jellyfish are called ephyrae. Jellyfish begin their life cycle as larvae. The larvae float in the currents until they attach to a rock. Once they attach to the rock, they are known as polyps. Polyps eventually bud into ephyrae.
Jellyfish consist of approximately 98 percent water. Though called a fish, they are actually a type of plankton. They are transparent and bell-shaped, with no bones, brain or heart. Jellyfish float in the water and range in size from less than 1 inch to nearly 7 feet long. Tentacles can reach as long as 100 feet. Mature jellyfish live for about 3 to 6 months.