Jellyfish

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A number of the usually deep jellyfish are not transparent, and instead have dark or red coloring, such as this one, called Periphylla. (Photo by Larry Madin, WHOI)

Jellyfish live in all oceans, from the surface to very deep water where there is no light. They have simple umbrella-shaped bodies that are soft and jelly-like, or gelatinous, without much internal structure. Most are at least partly transparent. They move by contracting their bodies and forcing water out the open end, pushing them forward. All jellyfish are predators: they have tentacles that carry stinging cells that they use to catch and eat smaller ocean animals, including copepods, krill, and larval fish.

Many jellyfish species that live in deep water in warmer parts of the ocean live close to the surface in polar regions where the water is very cold all year. A number of the usually deep jellyfish are not transparent, and instead have dark or red coloring, such as this one, called Periphylla.

Kingdom: Animalia
Phylum: Cnidaria

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