Coral reef islands and atolls. The reef face is the zone above the reef floor or the reef drop-off. This zone is often the reef's most diverse area. Coral and calcareous algae provide complex habitats and areas that offer protection, such as cracks and crevices. Invertebrates and epiphytic algae provide much of the food for other organisms. A common feature on this forereef zone is spur and groove formations that serve to transport sediment downslope. The reef flat is the sandy-bottomed flat, which can be behind the main reef, containing chunks of coral. This zone may border a lagoon and serve as
Coral reef fish complexity and diversity inherent in coral reef ecosystems, the wide variety and temporal availability of food resources available to coral reef fishes, a host of pre and post larval settlement processes, and as yet unresolved interactions between all these factors. There are two major regions of coral reef development recognized; the Indo-Pacific (which includes the Pacific and Indian Oceans as well as the Red Sea), and the tropical western Atlantic (also known as the "wider" or "greater" Caribbean). Each of these two regions contains its own unique coral reef fish fauna with no natural overlap in species. Of the two