Jellyfish are one of the strangest, but also the most interesting organisms. These animals are cnidarians, easily recognizable by tentacles surrounding their mouth. With their gelatinous body of various colors and shapes, jellyfish are completely separated from the rest of the animal kingdom. They have no bones, brain or heart. For sense of sight, smell and orientation jellyfish use sensory nerves located at the base of their tentacles. They are found all over the world and are mostly a part of the plankton community. Plankton flora and fauna floats in the water column and their movement is governed by sea currents. Jellyfish have been living on Earth for over 650 million years and with thousands of different species, many more are yet to be discovered.