Knob Coral

About

Knob Coral (Astraeosmilia maxima) is a reef-building coral native to the Indo-West Pacific, found across a broad geographic range from the eastern coast of Africa out to the western Pacific islands. In the wild it grows in reef-associated environments from shallow water down to around 35 meters, meaning it tolerates a reasonable range of light and water conditions. The common name comes from its distinctive surface texture, with pronounced knob-like corallites that give the skeleton a bumpy, almost sculptural appearance. Like other hermatypic corals, it hosts zooxanthellae and depends on light-driven photosynthesis for much of its nutrition, though target feeding with small meaty foods can support good growth over time. In the aquarium it is considered reef safe and does not tend to be aggressive toward neighbors, though as with most hard corals, adequate spacing from other colonies is sensible practice. Moderate lighting and moderate flow suit it well, providing enough water movement to keep detritus off the surface without stressing the tissue. This is not a coral recommended for beginners, stable water quality and some experience with stony coral care will set you up for success, but it is a rewarding and visually interesting choice for a mixed reef display.