Coral colonies growing in shallow water are often heavily branched. In contrast, deeper water corals often grow in sheets or plates. These flattened forms allow for more efficient use of lower light intensities in deeper waters.
The growth rate of corals and coral reefs depends on factors such as light intensity, water temperature, salinity, turbidity, food availability, competition for space, and predation. Upward growth of coral colonies is generally between 0.5 to 4 in. (1-10 cm) a year.