They catch and eat smaller plankton, larval fish, invertebrates, small shrimp and even other jellies by using nerve cells to help them move and react to food. The tentacles sting the food, then the oral arms capture whatever comes in contact with the body structure. Cilia on the tentacles may be used to direct food toward the mouth. Digestion also begins outside the body when the jelly secretes enzymes onto the prey, then sweeps the partially digested food particles into its mouth. When food is in short supply, jellies have the unusual ability to shrink in size, thus requiring less food.
Jellies are a treat to eat for some people.
In Asian countries, notably Japan, they're salted and dried as a snack. The texture, reportedly, is crispy, yet elastic-like an old rubber band. In addition to people who eat jellies, it's quite common for jellies to become cannibalistic-to eat each other. Sea turtles, blue rockfish and ocean sunfish find them tasty too. Jellies are 97 percent water.