Green Cactus Coral

About

Green Cactus Coral (Madracis decactis) is one of the more interesting Atlantic and Caribbean reef corals to make its way into the hobby, and it stands out from the usual Indo-Pacific offerings in both form and color. Colonies grow in nodular, encrusting, or laminar shapes, with the nodules typically club-shaped and flattened. The individual corallites are circular to angular, widely spaced across the surface, and each sports a solid conical columella fused with, most distinctively, ten septa, which is the trait that gives this coral its common and scientific names alike. The coenosteum between corallites has fine spinules that can form low ridges, giving the surface a textured, almost granular look. Coloration runs from pale yellowish-green through deeper greenish-brown, with branch tips that tend to be lighter. Specimens from Brazilian waters often show a bluish-grey cast instead, which sets them apart visually. In the wild this species turns up across a huge depth range, from shallow reef crests down to nearly 100 meters, suggesting it can handle varied light conditions, though in the aquarium it does best under strong lighting with robust flow. Rated intermediate in care, it is a rewarding choice for reefers who already have some experience keeping demanding SPS or LPS corals.