Atolla jellyfish

About Atolla Jellyfish

Atolla jellyfish, or crown jelly, could be considered the royalty of their gelatinous family. All six Atolla species are distinguished by a deep groove running through their bell, giving the impression of a transparent crown. 

Like all jellyfish, Atolla do not have a complicated digestive system, respiratory system, circulatory system, or brain. These jellies are not exactly discerning about what they eat. They’ll grab any prey animal swimming by with their tentacles, including a particularly long one that can coil up or extend. This tentacle might also be used for reproduction.

Like many other deep-sea jellies, some species of Atolla have a deep red hue. Since red light doesn’t penetrate to the Atolla’s favored depths of 1,000-4,000 meters, it actually appears completely black to predators, letting it hide in plain sight. 

Atolla are also bioluminescent, and give off flashes of blue light—a color that is visible in the deep ocean—possibly to attract or dazzle its prey. The blue flashes may also startle predators, or attract even bigger predators that can chase off its assailants. This strategy of deterrence has earned the species an apt nickname: the “alarm jelly.”


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Quick Facts

Common NameAtolla jellyfish
Scientific NameThere are several different species; Atolla sp. is the most common
Other Namescrown jellyfish, coronate medusa, alarm jelly
SizeDiameter ranges from one to eight inches. Length (with tentacles) ranges from 1.5 inches to 12 feet long.
Discovery1880 Atolla wyvillei, last 3 species discovered 1957-62
Eats what?Small crustaceans
Eats how?Traps prey with tentacles, in particalr a single, long, extendable one.
Is eaten by?Siphonophores, segmented worms, amphipods, fish. Some related species are also eaten by humans in Japan.
BioluminescenceYes, especially when attacked