Jellyfish in Jellyfish Lake, Palau, Micronesia. This footage shows how the jellyfish avoid the shaded regions of the lake. This is because they derive most of their energy from symbiotic algae that live in their body tissues, which produce food for the jellyfish from sunlight, using photosynthesis. Jellyfish Lake is a marine lake that is nearly completely cut off from the surrounding ocean, and the jellyfish in it have evolved into a unique subspecies, Mastigias cf. papua etpisoni.