Reef fish use the reef for cover and food. Corals on the reef vary from large stony heads to whispy branches. Tiny coral animals build massive reef structures. Staghorn corals have declined at Caribbean reefs in the past 20 years. Florida Keys 126.
Brain corals get their name from the folds and turns in the coral skeleton.
The diversity of fish and other reef organisms rival tropical rainforests. Florida Keys 1972 May 128. Bioerosion of coral reefs makes them brittle and susceptible to collapse. Like corals, glass sponges are also partly composed of calcareous material. Staghorn corals form the forests of the reef.