Asterias has a bilateral symmetry only at the larval stage, but it attains five–fold symmetry as an adult. It is a genus of the Asteriidae family of sea stars. This genus contains a total of six species. Generally, 5 arms are found in Asterias, but, in some cases, it may be more than five. For example, there are 7–14 arms in Solaster and more than 40 arms in Heliaster