Although they may look harmless, the tentacles of the sea anemone can deliver a poisonous sting strong enough to immobilize a passing fish. Once the fish has been paralyzed, the anemone uses these tentacles to maneuver the fish towards the mouth at its center. Sea anemones are closely related to corals. They are found on coral reefs and rocky outcrops all over the world. They can grow as large as 6 feet (1.8 meters) in diameter and are found at all depths of the ocean. They have even been found several miles down in deep ocean trenches.