The city of Monterey, California, has one of the finest aquariums in the world, including extensive displays of jellyfish. Mostly these jellyfish are bobbing around in a simulated current, almost always with the “bell” portion of their bodies up, and the tentacles hanging down and propelling the organism along.
A curious creature in the exhibit is the Upside-Down Jellyfish, also known as the Cassiopeia Jellyfish. As the name implies, these organisms lie on their flattened bell (head), with tentacles extending up into the water. The tentacles catch plankton for food and absorb light that is used by photosynthetic algae living in the jellyfish’s body. These exhibits are brightly lite to encourage photosynthesis, which also makes it easy to get good clear photographs.
In the natural world these jellyfish live in mangrove swamps and shallow waters in Florida and the Caribbean. Its sting is mildly toxic and is barely noticeable to most people (although sensitive individuals can have a strong reaction).