In Indonesia, 25 percent of the coral reefs are in good condition and 6 percent are considered excellent. In the Philippines, more than 460 species of hard corals have been identified at no fewer than 50 reef sites in recent years. Singapore has a small area of fringing and patch reefs, with more than 200 species of corals recorded. More than 250 species of corals have been documented living in the reefs of Thailand, with reef conditions ranging from very good to very poor. Vietnam shows high coral diversity, with more than 300 species of corals recorded in the region. The islands of Fiji contain vast barrier and fringing reefs, many of which are in good or excellent condition. Micronesia is a vast and scattered chain of islands hosting more than 3,100 square miles of reefs, and French Polynesia possesses an estimated 8,000 square miles of reef formations.
According to the California Academy of Sciences, the most common groups of corals in Indo-Pacific coral reefs are hard corals and soft corals. The hard, stony corals (scleractinians) constitute one of the most diverse coral groups. Scleractinians have thick calcium carbonate skeletons with large polyps. Common scleractinians include Acropora, Fungia, Montipora, Pocillopora and Turbinaria. Soft corals (octocorals) have a flexible skeleton that allows them to move with the ocean currents. Examples of octocorals include sea fans, sea whips, sea pens and leather corals.
Less common species found in Indo-Pacific coral reefs include the stinging, or fire, corals (hydrocorals), whose stings are among the most toxic of all corals. Hydrocorals have calcium carbonate skeletons with tiny pores and stinging polyps. Black, or thorny, corals (antipatharians) are also found in the Indo-Pacific region. Antipatharians are covered with both thornlike projections and a thin tissue that imparts a bright yellow or green color.
According to Florent's Guide to the Tropical Pacific Reefs, many species of polyp-eating butterflyfish inhabit the Indo-Pacific region, attracted by healthy coral reefs. Common herbivorous fish include angelfish, surgeonfish and rabbitfish, all of which keep the reef free of algae overgrowth. Damselfish, chromis and anemonefish also populate Indo-Pacific reefs in large numbers. Bottom-dwelling reef fish inhabitants of Indo-Pacific Reefs include gobies, blennies, hawkfish, lionfish and pipefish. Various species of groupers, snappers, parrotfish, wrasses and eels feed on smaller Indo-Pacific reef fish, and sharks and sting rays feed on the larger reef fish. Hawksbill, green and loggerhead sea turtles as well as bottlenose dolphins are also common in Indo-Pacific reefs.
A diverse range of crustaceans live in Indo-Pacific reefs, including lobsters, shrimp, crabs, hermit crabs, barnacles and mantis shrimp. Worms and mollusks also thrive in the Indo-Pacific region. Many types of colorful worms, flatworms, slugs and nudibranchs sift the sand and clear the reefs of algae. Octopuses and cuttlefish are common, as well as gastropods, bivalves and sea anemones. Giant clams are especially diverse in the Indo-Pacific reef region. Sea stars, sea urchins and sea cucumbers, which are sand sifters that eat detritus and algae, also inhabit the Indo-Pacific region.
