I am a cnidarian (snid-DARE-eeyan). That means I have a sac-like body with a mouth and tentacles on top. Jellyfish and corals are also cnidarians.
When I am young and very small I attach myself to a rock or dead coral. I can then grow to over 3 feet (1m) wide, and my tentacles can grow to 3 inches (7.5cm) long. I can get huge and pretty much stay in one place my whole life.
I live in a symbiotic, or close, relationship with a group of clown fish. The clown fish have a protective slime layer that keeps them from getting stung by my nematocysts. I eat food that they drop, and they protect me from my predators. In return, I give them a safe place to live. Because the clown fish help me and I help the clown fish our relationship is mutualistic -- we both benefit!
Many people think I'm a plant, but I'm an animal and a predator! I use my many tentacles to find my prey and when they brush up against me I shoot thousands of poisonous stinging cells, or nematocysts, into them! My stinging cells don't kill humans, but they are very painful!
I can also grab prey with my tentacles and bring them to my mouth to eat. I use my mouth for eating and also to spit out waste! I don't have a gut that goes all the way through my body like humans.
I will eat almost anything that floats by. One of my favorite things to do is to wait for small, delicious crabs, shrimps and fish to float by unsuspectingly. When they do, I pull a surprise attack on them, grab them with my long tentacles, and GULP! (They never knew what hit them!). I only eat other animals, so I am a carnivore.
People take me to sell for aquariums, but I don't make a good aquarium animal because I eat the other fish in the tank!
Reefs are in danger, and that means so is my home!