Underwater, they are quite beautiful as their tentacles open up like flowers. Adults feed on small plankton that they capture with their stinging cells, or nematocysts. They are preyed upon by several different kinds of animals, such as nudibranchs and sea stars. Sea anemones are bottom-dwelling, sedentary marine animals that can be found living in a variety of habitats. They are one of the simplest animals, but the nematocysts that cover their tentacles are one of the most complex structures in the animal kingdom.
Many anemones live in close association with other organisms.
Some species host symbiotic algae within their cells, which may be a major source of energy for them. The algae perform photosynthesis and provide energy resulting from that process to the anemones. Eupagurus prideauxi are always found living together, never alone. When a crab adopts a shell for its home, it finds an anemone and places it on the top of the shell. When it outgrows the shell and moves to a new one, it moves the anemone as well.