As the name suggests, brain coral has a spherical shape and irregular groves that makes it resemble the brain. It is formed by millions of polyps that come together as colonies. These polyps secrete hard Calcium Carbonate which forms the strong brain coral. These corals can be found in shallow areas of the warm sea and can grow up to a height of 1.8m.
Brain corals use tentacles to catch their food which consists of small moving animals (Dubinsky and Stambler 359). They also have a symbiotic relationship with the algae that live within them, from where they obtain nutrients. During the night, the most common genera of Brain corals, Favia, stings other corals using its extended sweeper tentacles (Dubinsky and Stambler 357). It then sucks nutrients from these other reefs such as soft corals. Due to their hard texture and surface, they reduce the force by which moving water hits other coral,s such as sea fans and soft corals, during hurricanes.
They do not produce Calcium Carbonate skeletons, thus, are fragile and are easily damaged by hurricanes and sea animals. They are formed by sclerites which have a hard skeleton, thus, offer them support (Haywood and Sue, 208). Most of them are found in areas where water is rich in nutrients and where is little amount of light. Soft corals provide a habitat to fish, snails and some algae. They rely on other harder reefs for protection from fast moving sea animals and waters. Among the corals that protect soft corals are the brain corals that reduce the speed of water, especially during hurricanes.
Sea fans are found in tropic and subtropic seas. They are formed from polyps and form fan-like branched structures and, hence, obtained their name (Borneman 464). They appear in different bright colors such as red, yellow or purple. They can be over 2 meters in height and up to a foot in thickness. They are found in shallow waters (Borneman 464). Polyps in sea fans have eight tentacles each, which they use to catch planktons and other food and the ‘fans’ help in filter-feeding. Some of these coral organisms contain algae which thrive in a symbiotic relationship. Sea fans harbor other organisms such as pygmy seahorse and brittle stars.