This genus of sea anemone is common throughout the world's oceans. The plumose anemone, Metridium senile , is found off both coasts of North America and is often used as a specimen for dissection in the classroom. It is usually white but also occurs as tan, brown, or orange. Plumose anemones are often found attached to docks and pilings and look like gelatinous blobs when the tide is out. 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.