Crown jellyfish Crown jellyfish Crown jellyfishes are the six families of true jellyfish that belong to the order Coronatae. They are distinguished from other jellyfish by the presence of a deep groove running around the umbrella, giving them the crown shape from which they take their name. Many of the species in the order inhabit deep sea environments. Crown jellyfish are able to make light through bioluminescence. When they are touched, their bells will light up. Otherwise, the bell of a crown jellyfish will look transparent when undisturbed. When they are attacked, crown jellyfish are able to startle, mislead, and distract their
Jellyfish disperse widely and is followed by a sedentary polyp phase. Jellyfish are found all over the world, from surface waters to the deep sea. Scyphozoans (the "true jellyfish") are exclusively marine, but some hydrozoans with a similar appearance live in freshwater. Large, often colorful, jellyfish are common in coastal zones worldwide. The medusae of most species are fast growing, mature within a few months and die soon after breeding, but the polyp stage, attached to the seabed, may be much more long-lived. Jellyfish have been in existence for at least 500 million years, and possibly 700 million years or more,