Chrysaora pacifica, commonly named the Japanese sea nettle, is a jellyfish in the family Pelagiidae. This common species is native to the northwest Pacific Ocean, including Japan and Korea, but it was formerly confused with the larger and more northerly distributed C. melanaster. As a consequence, individuals kept in public aquariums have often been mislabelled as C. melanaster. The medusae of C. pacifica typically has a bell with a diameter of 15–21 cm (5.9–8.3 in). Its sting is strong and can be dangerous to humans.