Each of these cells contains a nematocyst which acts like a mini-harpoon. When a jellyfish touches something the nematocyst is released and injects toxin into the prey. The Aquarium has moon jellies, Aurelia spp. They have a transparent, white bell rimmed with hundreds of short tentacles. They have four oral arms, frilled along one edge, which hang from the centre of the bell.
Moon jellies range from the Arctic to Florida and from Alaska to southern California.
If you touch their tentacles their sting will not kill you, unless you are allergic to the toxin, otherwise it will probably feel tingly, but some say they don't feel anything when stung by a moon jelly. The moon jellies at the Aquarium are fed a daily meal of larval brine shrimp that have been enriched with fatty acids as well as frozen plankton once a week. They can live in the polyp, or budding, stage for as long as 5 years or more. During the medusa stage the jellyfish may live for several months. A jelly can regenerate small amounts of tissue that has been damaged.