Family Labridae: Wrasses (43 species in Hawaiian waters)

The wrasses are brightly colored and cigar shaped. They are diurnal carnivores, generally feeding on small invertebrates on the reef. The Cleaner Wrasse (Labroides phthirophagus), however, has an unusual food source. They set up cleaning stations around coral heads in the reef where other fishes will go to get cleaned. The cleaner wrasse pick off parasites from their skin and gills, as well as dead skin and mucus. Many wrasse species bury themselves in the sand at night or when frightened. In most species, most individuals start out as females. Some adult females change into more brightly colored males, called "terminal males". (They are called terminal because they never change back to female and remains male for the rest of their lives.)

Adult wrasses are sexually dimorphic (males and females look very different). Many species of animals are sexually dimorphic, sometimes there is a big difference in size such as with gorillas; sometimes there are special features such as the beautiful tail of a male peacock. In the case of wrasses the coloration of the two sexes is very different. Wrasses generally live in groups consisting of several females and one male. If the male is removed, one of the females will change into a terminal male. They lay pelagic eggs.

Family Scaridae: Parrotfish (7 species in Hawaiian waters)

Parrotfishes are related to the wrasses and swim with their pectoral fins, but are herbivorous. Their teeth are fused and form a parrot-like bill that is used to scrape off algae from coral limestone or bite off pieces of live coral. They chew up the coral skeleton and digest the organic matter inside. They eliminate the remaining grains of chewed-up calcium skeleton.

Their gastro-intestinal tract lacks a stomach, but has a very long intestine. They are diurnal, and like the wrasses, individuals of most parrotfish species start life as a female and undergo sex and color changes as they grow older. In Hawai'i, males are blue-green in color and females are muted reds and gray. At night they often secrete a mucus coat that is thought to prevent their scent from being detected by sharks, moray eels and other nocturnal predators.

Family Pomacentridae: Damselfish (14 species in Hawaiian waters)

Damselfish are diurnal with two different feeding patterns, some are planktivores and some are herbivores. The planktivores hover in groups over coral heads in the reef, picking out their tiny prey from the water. Some of the herbivores, such as the Pacific Gregory (Stegastes fasciolatus), maintain gardens within their territories, weeding out unwanted algae species so that their preferred food species can flourish. The damselfishes represent one of the most abundant fish families on the reef. They lay eggs in patches on the bottom that are guarded by the males. They therefore tend to protect their territories very aggressively, keeping other fishes from feeding on their algae gardens and their eggs. Once the eggs hatch, the larval damselfish will spend days or weeks as part of the pelagic zooplankton before settling in a distance reef environment.

Family Acanthuridae: Surgeonfish (23 species in Hawaiian waters)

Almost all surgeonfish species, including the Tangs, are herbivores. Surgeonfish are often seen swimming in small groups, using their small incisor-like teeth to scrape algae off the rocks or bottom. Sometimes they will form feeding aggregations to overwhelm the territorial damselfishes and feed on their algal gardens. A few species feed on zooplankton in the water column. Just like the parrotfishes, another herbivore, the surgeonfishes have very long intestines. They are diurnal and spawn in the water column. Their eggs are pelagic and after hatching the larval fish drift as part of the plankton. Surgeonfish are pectoral fin swimmers when feeding.

Family Zanclidae: Moorish Idol (1 species World wide, including Hawai'i)

The Moorish Idol (Zanclus cornutus) is closely related to the surgeonfishes -- it swims with the pectoral fins but it lacks the scalpel-like tail spines. It occasionally feeds on algae, but specializes in feeding on sponges, a food that most fishes stay away from. Because sponges are toxic and have sharp needles or spikes embedded throughout the body as a type of skeletal support, they are a challenge for any fish to eat and digest. Moorish Idols are diurnal and lay pelagic eggs.

Family Chaetodontidae: Butterflyfish (24 species in Hawaiian waters)

Butterflyfishes have small, terminal jaws, with bristle-like teeth. They mostly specialize in feeding on coral polyps, although the diet in some species may include algae, benthic (bottom-living) invertebrates, or zooplankton. When feeding on coral, the butterflyfishes tend to bite off individual coral polyps (the soft parts) of a few adjacent polyps. It is often possible to determine which species fed on a particular coral by looking at the particular damage done. Butterflyfish are diurnal, lay pelagic eggs, and swim mainly with their tails. Their coloration generally includes a dark bar across the eye to disguise it. Many of the coralivorous butterflyfish species are found in pairs that maintain a relatively large territory against other butterflyfishes, mostly of the same species. This is probably to reduce the damage done to each coral head and ensure a healthy food source. The pair thus constantly patrols their territory nipping pieces of coral here and there.

Family Pomacanthidae: Angelfish (5 species in Hawaiian waters)

Different angelfish species have different feeding behavior. The dominant food sources are sponges, tunicates and benthic algae. In some angelfish species, most, if not all individuals begin life as a female, just as is seen in parrotfishes and wrasses. Some adults change into males. In some species, the coloration of the two sexes differ somewhat, but not as drastically as seen in some of the other families. Angelfish are diurnal, territorial and found either alone or in pairs. They lay pelagic eggs.