Jellyfish

Jellyfish are free-swimming marine invertebrates belonging to the phylum Cnidaria. They possess a gelatinous, bell-shaped body (called a medusa) with trailing tentacles armed with stinging cells (nematocysts) used for capturing prey and defense. Jellyfish are found in oceans worldwide, from coastal waters to the deep sea. They lack brains, hearts, or bones, moving via a simple nerve net and the pulsing of their bell. Their diet includes plankton, small fish, and crustaceans. Some jellyfish species are highly venomous and can pose a threat to humans.