Can you tell the difference between the corals and the plants? Look closely! Click on image for full size (18K JPG ) Windows Original, adapted from Corel Photography

Cnidarians are animals with stinging cells called cnidoblasts. This includes corals, jellyfish and anemones. Cnidarians do not have a head, and commonly look like a flower. The petals are actually tentacles which contain the cnidoblasts. There are over 9000 species living today.

Corals are often mistaken to be plants. In reality, there are both soft and hard corals, but all of them are animals. Hard corals form coral reefs, which serve as a home for many sea creatures. Without them, many marine animals would become extinct. Hard corals have two parts: a hard outer shell called a corallite, and soft tissues called polyps. Corals are so pretty that some people make reef aquariums.

Jellyfish are different from corals in that they can move around in the water. The typical jellyfish has a round, bowl-shaped top with tentacles handing down. Although they are very pretty, jellyfish should be avoided because their stings can be very dangerous. They come in a range of sizes, from a few inches to 3 feet.