Galaxy Coral

About

Galaxy coral (Galaxea fascicularis) is one of the more recognizable large-polyp stony corals in the Indo-Pacific, found across an enormous range stretching from Japan and Egypt down to Australia and Tahiti. In the wild it grows in sheltered reef zones away from heavy surge, and it can reach truly impressive sizes. Colonies regularly exceed five meters across, forming either broad domes when young or massive columnar structures as they mature. Each corallite is fairly small, usually under ten millimeters wide, but the coral makes up for that with dense, tightly packed polyps that sport tentacles tipped in white. Those tentacles are extended during the day, which is what gives this coral its distinctive galaxy-like appearance and earns it its common name. Coloration runs from green and grey to brown and red, often with contrasting hues between the body and the tentacles. In the aquarium, Galaxy coral falls into intermediate territory. It adapts reasonably well to moderate light and flow, but it's worth knowing this species is an aggressive sweeper. Those daytime tentacles can extend surprisingly far beyond the coral's visible edge, and it will sting neighboring corals, so give it generous spacing on the rockwork. A rewarding species once you plan around its territorial nature.