Birch Aquarium - Jelly Fish - as part of the expert series by GeoBeats. Anyone who has been to the beach knows about jelly fish. People are always talking about getting stung and being fearful of jelly fish but, these are really amazing, beautiful animals. Jelly fish are made up of ninety-five percent water. They do not have any brain structure or any organs. They are really simple creatures that float in the ocean and use their tentacles to help sting and catch prey. And then they bring the prey up into their mouth and then any waste comes out, out of their mouth. So, jelly fish are a remarkable species. They have been around for millions and millions of years and have a really incredible life history. Especially, locally in San Diego, you do not really have to be that scared of jelly fish. We have moon jellies here but the sting is very mild. And basically, the jelly fish only think that you might be prey for them and when they sting you, they realize that you are not.