Millions of years ago, jellyfish were trapped in this lake after a submerged reef rose from the sea, creating a landlocked saltwater lake. In this lake, the jellyfish have adapted to the new conditions by losing their sting. They have eight primitive eyes and algae that live within their cells. These algae are what the jellyfish live on. Twice each day, the jellyfish in the lake swim from one side to the other. The jellyfish do this to get sunlight to their internal algae so that the algae can grow. At night the jellyfish swim to a lower depth where the water is rich in nitrogen. The nitrogen also sustains the algae population. The jellyfish has only one main predator in this lake – the sea anemone. Jellyfish can be stung, trapped, and killed by these creatures.