Coral reefs occupy less than 1% of the surface area of the world oceans, but provide a home for 25% of all marine fish species.

[2] As an example of the adaptations made by reef fish, the yellow tang is a herbivore which feeds on benthic turf algae.

When alarmed, the usually placid yellow tang can erect spines in its tail and slash at its opponent with rapid sideways movements.

[3] The mechanisms that first led to, and continue to maintain, such concentrations of fish species on coral reefs has been widely debated over the last 50 years.

These include the rich habitat complexity and diversity inherent in coral reef ecosystems,[4][5] the wide variety and temporal availability of food resources available to coral reef fishes,[6] a host of pre and post-larval settlement processes,[7] and as yet unresolved interactions between all these factors.

[8] 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).

For this manoeuvrability is more important than straight line speed, so coral reef fish have developed bodies which optimize their ability to dart and change direction.

When escape is not possible, the butterflyfish will sometimes turn to face its aggressor, head lowered and spines fully erect, like a bull about to charge.

[20] This is a form of countershading: from below, the white spots look like the lighted surface of the water above; and from above, the fish blends more with the coral reef below.

Their mouths protrude like forceps, and are equipped with fine teeth that allow them to nip off such exposed body parts of their prey.

Parrotfishes eat algae growing on reef surfaces, utilizing mouths like beaks well adapted to scrape off their food.

The water is then expelled through the gills with the mouth closed, thereby trapping the helpless prey[14] For example, the bluestripe snapper has a varied diet, feeding on fishes, shrimps, crabs, stomatopods, cephalopods and planktonic crustaceans, as well as plant and algae material.

[24] Goatfish are tireless benthic feeders, using a pair of long chemosensory barbels (whiskers) protruding from their chins to rifle through the sediments in search of a meal.

[28] Large schools of forage fish, such as surgeonfish and cardinalfish, move around the reef feeding on tiny zooplankton.

For this they have evolved special pressure sensors along their sides, called lateral lines, that let them feel each other's movements and stay synchronized.

Barracuda are ferocious predators on other fishes, with razor-sharp conical teeth which make it easy for them to rip their prey to shreds.

Barracuda patrol the outer reef in large schools, and are extremely fast swimmers with streamlined, torpedo-shaped bodies.

[23] The bluestreak is marked with a conspicuous bright blue stripe and behaves in a stereotypical way which attracts larger fish to its cleaning station.

The four largest groups of coral reef fishes that feed on plants are the parrotfishes, damselfishes, rabbitfishes, and surgeonfishes.

Algae are primary producers, which means they are plants synthesising food directly from solar energy and carbon dioxide and other simple nutrient molecules.

One important algal group, the bottom dwelling (benthic) algae, grows over dead coral and other inert surfaces, and provides grazing fields for herbivores such as parrotfish.

[23] Damselfish are a group of species that feed on zooplankton and algae, and are an important reef forage fish for larger predators.

The tentacles of sea anemones bristle with tiny harpoons (nematocysts) primed with toxins, and are an effective deterrent against most predators.

Venomous fish tend to be either very visible, using flamboyant colours to warn enemies, or skilfully camouflaged and maybe buried in the sand.

[39] The spotted trunkfish is a reef fish which secretes a colourless ciguatera toxin from glands on its skin when touched.

It is a delicacy in some cultures (the venom is destroyed when it is cooked), and can be found for sale in some fish markets with the electric organ removed.

[46][47] Outbreaks of ciguatera poisoning in the 11th to 15th centuries from large, carnivorous reef fish, caused by harmful algal blooms, could be a reason why Polynesians migrated to Easter Island, New Zealand, and possibly Hawaii.

[50] They feed mainly on bony fishes, including eels, squirrelfishes, snappers, damselfishes, parrotfishes, surgeonfishes, triggerfishes, and goatfishes, as well as octopus, spiny lobsters, and crabs.

They are found over continental and insular shelves, preferring the leeward (away from the direction of the current) sides of coral reefs with clear water and rugged topography.

[61] The Caribbean reef shark feeds on a wide variety of reef-dwelling bony fishes and cephalopods, as well as some elasmobranchs such as eagle rays and yellow stingrays .