White Moon jellyfish also called the moon jelly, moon jellyfish, common jellyfish, or saucer jelly. usually about 25–40 cm in diameter. eats medusae, plankton and mollusks. capable of limited motion, drifts with currents.All species in the genus are closely related. found throughout most of the world's oceans at water temperatures ranging from 6 to 31°C. MINT