Knob Coral

About

Knob Coral (Dipsastraea matthaii) is a large polyp stony coral that earns its common name from the distinctly raised, rounded corallites that give the colony a bumpy, textured surface. Each corallite sits slightly proud of the shared skeleton, creating a pattern that makes this species fairly easy to pick out among similar faviid-type corals. In the wild, Dipsastraea matthaii forms solid, dome-shaped or encrusting colonies across reef environments with a broad distribution, generally found on reef flats and upper slopes where light and water movement are reasonably consistent. It falls into the intermediate care bracket, which in practice means it is tolerant and not particularly fussy, but it does benefit from a keeper who understands basic reef water quality and stability. It is fully reef safe and poses no meaningful threat to neighboring corals provided it has adequate space. Like most stony corals, it can extend sweeper tentacles at night, so placing it with a little room to grow is sensible. Moderate lighting and moderate flow suit it well, and it rewards consistent conditions with steady, if unhurried, growth. Not a beginner's first coral, but a rewarding and durable addition once you have the fundamentals down.