Jellyfish Fossil range: 505 mya to present Cambrian – Recent
Pacific sea nettle (Chrysaora fuscescens) at Monterey Bay Aquarium
Scientific classification
Kingdom: Animalia Phylum: Cnidaria Subphylum: Medusozoa
Included groups
Scyphozoa — true jellyfish Cubozoa — box jellyfish Staurozoa — stalked jellyfish Hydrozoa — small jellyfish
Cladistically included but traditionally excluded groups
Hydroidolina – some hydrozoa

White-spotted jellyfish

Jellyfish are animals of the phylum Cnidaria. They are a monophyletic clade, the Medusozoa. Most of them live in the oceans, in salt water, where they eat small sea animals like plankton and little fish, and float in the sea. Only a few jellyfish live in fresh water.