Moon Jellyfish

Moon Jellyfish

Aurelia aurita


When deprived of food, they can shrink to 1/10th of their size to save energy.

Exhibit Name and Location:
Baltimore - Jellies Invasion: Oceans out of Balance

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Moon Jellyfish Moon Jellyfish Moon Jellyfish Moon Jellyfish Moon Jellyfish

Moon Jelly

The moon jelly has translucent white, saucer-shaped bell, with a blue-gray transparent disk at its center through which the horseshoe-shaped gonads are visible. Short, delicate, fringe-like tentacles hang from the bell margins.

When deprived of food, they can shrink to one tenth of their original size to save energy. They redevelop to normal size when food is available.




Bell can be up to 12 inches wide, about the size of a dinner plate.


Temperate and tropical oceans worldwide; near the surface of shallow bays and harbors

Population Status

In the past, jelly populations were kept in check by predators like sea turtles and jelly-eating fish. Due to the reduction of these predators, jelly populations are growing at alarming rates.


Sea turtles and other jelly-eating animals such as tuna, sunfish, butterfish and spiny dogfish keep the jelly populations in balance. All seven species of sea turtles include them in their diets. The largest sea turtle species, the leatherback, depends on jellies for food. Because jellies are more than 90 percent water and an adult leatherback can weigh more than 2,000 pounds, one turtle can consume a lot of jellies.

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Jack Cover
General Curator

pressroom striped fish

As the general curator, Jack's role is to ensure that our living animal collections are thriving and diverse, to best exhibit the beauty of the wild habitats we represent here at the Aquarium. Learn More

A Note From the Caretaker

This is our most prolific species in Jellies Invasion: Oceans Out of Balance. We are able to control culturing life-cycle stages through manual temperature manipulation. Petri dishes covered in polyps (sedentary stage) of this species spend three weeks in a refrigerator.

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