Sea anemone
From Conservapedia
Sea anemones are invertebrate animals that live in the ocean. They resemble upside-down jellyfish, and have sharp stinging tentacles arranged on their faces, and stalks like tree trunks down below. Anemones comes in many different colors, such as red and green, and they often live on coral reefs.
Clownfish have a symbiotic relationship with sea anemones, which means that the anemones live on food dropped by the clownfish, and in exchange protect the clownfish from predators like sharks.