Jellyfish, that is! It takes a lot of moon jellies (between 150 and 200) to fill our popular Ring of Life exhibit—and that’s why we grow our own, behind the scenes in small tanks called “kreisels.” The jellies start out as polyps and, in about six to eight months, when juveniles have matured to a larger size, they can be moved into the exhibit.
Growing the jellies is pretty simple compared to maintaining their exhibit, which must be cleaned—from the inside! by a diver!—every three months. Before that can happen, all the jellies are removed and placed in holding behind the scenes. Then a diver meticulously cleans every inch of the acrylic (a really big job when you consider the exhibit is 12 feet tall at its high point!). With the scrubbing done, the exhibit is drained and partially filled with freshwater and hydrogen peroxide to sterilize it. Then the exhibit is flushed and refilled with seawater before the jellies are added back.
While moon jellies can live over 10 years (and possibly more) when under human care, jellies in general have been around for far longer: hundreds of millions of years—since before dinosaurs roamed the earth. And they’re related to lots of interesting animals, including many that can be found in our exhibits: sea anemones, sea pens, sea fans, sea whips, and soft and stony corals.
Want to learn more about moon jellies? Read our fact sheet—and ask questions during your next visit to the Aquarium!