The word "Acan" has become synonymous with a few different types of corals that are all very similar in appearance and care requirements. This guide will focus on a true Acan, the Acanthastrea Echinata. The Acan echinata, also known as the "starry cup coral," is a species of coral in the Lobophylliidae Family. The thick-walled, circular corallites of the Acan can appear joined directly to one another by fused walls (cerioid) or joined by fused compound walls (subplocoid). The vertical plates in the walls (or septa) have large toothy projections. The skeleton is covered with folded, fleshy tissue. Appearing uniform in color or mottled, the Acan can be found in seemingly endless color combinations and patterns. Acans are a truly beautiful addition to any reef.