Cave Star Coral

About

Cave star coral (Madracis pharensis) is one of the more intriguing small-polyp stony corals available to reef keepers, partly because it behaves quite differently depending on where it originates. Colonies collected from Mediterranean waters are typically azooxanthellate, meaning they lack the symbiotic algae most reef corals depend on, while Atlantic and Caribbean specimens are generally zooxanthellate and capable of photosynthesis. This geographic quirk makes sourcing history genuinely relevant when you're figuring out how to keep one. In terms of appearance, colonies grow in an encrusting or nodular form, staying relatively low-profile against the rockwork. The corallites are compact and slightly angular, with two alternating cycles of septa and ten primary septa fused to a central columella. Color runs from red and pink through grey to green, and the presence or absence of zooxanthellae plays a direct role in which end of that spectrum a given colony lands on. In the wild, this species tends to favor deeper, lower-light zones and is reef-associated across a broad tropical to subtropical range spanning the eastern Atlantic, Caribbean, and into the Mediterranean. Given its intermediate care rating and requirements for solid flow and good lighting, it's best suited to keepers who already have a handle on the basics of small-polyp stony coral husbandry.