Most established coral reefs are between 5,000 and 10,000 years old.
Different species of coral grow at different rates depending on the type of coral, water temperature, water turbidity, availability of light, oxygen level, amount of turbulence, and availability of food. In general, massive corals tend to grow slowly, increasing in size from 0.5 cm to 2 cm per year. In contrast to the massive species, branching colonies tend to grow much faster, and under favorable conditions, these colonies can grow vertically by as much as 10 cm per year.
Image: Recessed large polyps of Goniastrea sp., commonly known as brain star or honeycomb coral, viewed from the side. Live coral specimen in artificial seawater imaged with Olympus MVX Fluorescent Macroscope and filters from Chroma Technology.
Credit: James H. Nicholson, NOAA.