Violet Lace Corals in Surf zone, Distichopora violacea, Christmas Island, Australia

Colorful tunicates, sponges, hydroids, and other invertebrates grow on a reef in Raja Ampat, Indonesia.

Vibrant sea cucumbers, tunicates, hydroids, and other invertebrates cling to a reef in Raja Ampat, Indonesia.

Vibrant tunicates, sponges, hydroids, and echinoderms grow on a coral reef among the remote, tropical islands of Raja Ampat, Indonesia.

Spanish shawl nudibranch.

Beached Portuguese man-of-war (Physalia physalis), Praia do Forte, Bahia, Brazil, South America

Nudibranch (Cratena peregrina). Sardinia, Italy Restricted Resolution (Please contact us)

Nudibranch (Cratena peregrina). Sardinia, Italy (RR)

Nudibranch (Species unknown). Sardinia, Italy Restricted resolution (Please contact us) (RR)

Nudibranch (Cratena peregrina). Sardinia, Italy

Crab preying on dead portuguese man-of-war (Physalia physalis), Praia do Forte, Bahia, Brazil, South America

Deep-sea Jellyfish

Portuguese Man of War, Physalia physalis, Azores, Atlantic Ocean, Portugal

Portuguese Man of War, Physalia physalis, Azores, Atlantic Ocean, Portugal

Portuguese Man of War, Physalia physalis, Azores, Atlantic Ocean, Portugal

A tiny Benthic Hydromedusa, with a bell size of less than one centimeter, (Ptychogastria polaris), swimming in front of an iceberg, Tasiilaq, East Greenland

A tiny Benthic Hydromedusa, with a bell size of less than one centimeter, (Ptychogastria polaris), Tasiilaq, East Greenland

BLUE DRAGON (Glaucus atlanticus). A small peacic slug that measures only about 2 cm and is generally associated with the Portuguese frigatebird (Physalia physalis) or the blue button (Porpita porpita) on which it feeds. They can also appear in intertidal pools. Marine invertebrates of the Canary Islands, Tenerife.

BLUE DRAGON (Glaucus atlanticus). Small slug that measures only about 2 cm and is generally associated with the Portuguese man of war (Physalia physalis), although it also usually appears in intertidal pools. Marine invertebrates of the Canary Islands, Tenerife.

A tiny Benthic Hydromedusa, with a bell size of less than one centimeter, (Ptychogastria polaris), swimming in front of an iceberg, Tasiilaq, East Greenland

The Portuguese man o' war (Physalia physalis), also known as the man-of-war, a marine hydrozoan floating on the surface. Azores, Portugal, Atlantic Ocean.

A tiny Benthic Hydromedusa, with a bell size of less than one centimeter, (Ptychogastria polaris), Tasiilaq, East Greenland

A tiny Benthic Hydromedusa, with a bell size of less than one centimeter, (Ptychogastria polaris), Tasiilaq, East Greenland

A tiny Benthic Hydromedusa, with a bell size of less than one centimeter, (Ptychogastria polaris), Tasiilaq, East Greenland

A tiny Benthic Hydromedusa, with a bell size of less than one centimeter, (Ptychogastria polaris), swimming in front of an iceberg, Tasiilaq, East Greenland