A common clownfish in a sea anemone. The fish lives in a symbiosis with the anemone

Amphiprion melanopus anemonefish in a bubble anemone from anemonefish in a bubble anemone from East Timor

Sea anemones are Cnidarian animals that live in the sea. They are polyps, one of the basic forms of the phylum. They are predatory animals, which paralyse their prey with stinging nematocysts which fire a harpoon-like structure which delivers a dose of neurotoxins. To eat the fish, or crustacean, they move the prey into their stomach. Anemones are sessile (stay in one spot), but they can move if necessary.

The anemones have an oral disk on the top of its body. The sea anemone’s head is in the middle of the oral disk. The tentacles surround the oral disk. The pedal disc is on the bottom of the sea anemone.

Some sea anemones live in symbiosis with other animals. Clownfish, Bucchich's goby, and Sipder crabs find shelter among the tentacles of the anemone. Hermit crabs often have sea anemones on the shell they inhabit.