Brain corals are actually colonial animals. They can create
mounds 6 to 8 feet in diameter, and play an important role in
reef construction. Endosymbiotic algae within its cells gives
the coral its green color.
The symbiotic relationship is so efficient in recycling
minerals between the plant and animal that it gives brain
corals a dominant evolutionary advantage: they grow more
quickly. Collectively they are known as hermatypic corals
(from the Greek god Hermes, speedy messenger).