Scarids, which are widely known as parrotfishes because of their beak-like jaws, include approximately nine genera and 83 species. They are abundant in tropical reefs around the world and well known to divers for their striking coloration and noisy feeding as they crunch on dead coral. Parrotfishes exhibit several types of complex mating systems that vary more by geographic location than by species (see Reproduction). They also have considerable ecological impacts on coral reefs through herbivory and bioerosion (see Ecosystem Roles). (Choat and Bellwood, 1998; Nelson, 1994; Thresher, 1984)

Geographic Range

Parrotfishes are found primarily in tropical waters throughout the Atlantic, Indian, and Pacific oceans. However, some species inhabit subtropical waters, and some, such as Scarus ghobban, may venture far from reef environments. (Choat and Bellwood, 1998; Nelson, 1994)


Most parrotfishes exclusively inhabit offshore coral reefs in tropical regions. However, a few species feed primarily on sea grasses and are most common in the Caribbean. Two other species, Nicholsina denticulate and Sparisoma cretense, are common over rocky reefs of the Gulf of California and Mediterranean Sea, respectively. (Choat and Bellwood, 1998; Nelson, 1994)

Physical Description

Parrotfishes are characterized by their distinctive beak-like jaws, in which the teeth are fused together in most species, and a pharyngeal apparatus , which acts as a second set of jaws in the throat. In the pharyngeal apparatus, the teeth are arranged in rows and are highly specialized to grind, crop, and crush food as it is processed. Parrotfishes have large, cycloid scales , usually with 22-24 scales along the lateral line. The dorsal fin has nine spines and ten soft rays. The anal fin has three spines and nine soft rays, and the pelvic fins one spine and five soft rays. (Click here to see a fish diagram). (Choat and Bellwood, 1998; Nelson, 1994)

Some parrotfishes have a complex socio-sexual (socially influenced sexual change) system punctuated by three phases, and each phase change results in a different color pattern (See Reproduction: Mating Systems for a description of “phases” in parrotfishes). For instance, juveniles tend to have a drab mixture of browns, grays and blacks, but as they mature a distinct coloration emerges with the addition of red tones. A third set of colors is donned by males and by females that have recently undergone sex change into males. As these males mature, they exhibit bright, intricate patterns of reds, greens, and blues. This type of color change has been documented in Scarus, Sparisoma, Nicholsina, Bolbometapon, and Cryptotomus, but there are some monochromic (fishes that do not exhibit sexual color change) species that exhibit different types of sexual dimorphism. (Choat and Bellwood, 1998; Thresher, 1984)

Scarus coelestinus and Scarus coeruleus in the eastern Pacific and Scarus niger in the Indo-West Pacific exhibit no color differences. However, mature males of Scarus coelestinus and Scarus coeruleus develop more squared-off and prominent foreheads than smaller fish, while Scarus niger exhibits no physical differences other than size. Finally, fleshy tips on the upper and lower lobes of the caudal fin can be observed in mature males of Scarus rubroviolaceus, but are poorly developed on small males and females. (Thresher, 1984; Wheeler, 1985)

  • Sexual Dimorphism
  • male larger
  • sexes colored or patterned differently
  • male more colorful
  • sexes shaped differently
  • ornamentation


Tidal currents disperse parrotfish eggs, which begin to hatch approximately 25 hours after fertilization. Newly hatched larvae begin to feed after three days but the length of the planktonic stage is unknown. Most parrotfish species develop rapidly and reach maturity between two and four years. (Choat and Bellwood, 1998; Thresher, 1984)



The type of reproductive behavior described above and whether it involves paired, foraging group or mass spawning depends on a complex set of behavioral and geographic factors. For instance, some species, such as Scarus iseri, exhibit a wide range of reproductive behaviors depending on the area in which they are found. In Panama, Scarus iseri employs a system involving three classes of individuals: territorials, stationeries and foragers. Territorials are organized into groups that consist of a dominant female, several subordinate females and usually, but not always, a terminal (TP) male. Paired spawning occurs within the territory, which both males and females defend. Stationaries consistently use the same area for spawning but do not defend it, and foragers include groups of up to 500 individuals, mostly females. In Puerto Rico, initial phase (IP) and terminal phase (TP) individuals migrate to temporary spawning areas in deep water, usually in pairs. Finally, in Jamaica Scarus iseri emphasizes aspects of the foraging group system and spawning only takes place in groups. The three previous examples illustrate the flexibility of the socio-sexual mating systems found in parrotfishes. The reasons that different aspects of the basic spawning system manifest in different areas range from population density to competition for spawning sites and other resources to geographic factors like seasons and water temperature. (Thresher, 1984)


There is no evidence of parental behavior in parrotfishes. (Thresher, 1984)

  • Parental Investment
  • no parental involvement


The maximum age of most parrotfishes is less than 20 years and most live less than five years. There is a general trend in the scarids for larger species to live longer. Subsequently, the largest scarid, Bolbometopon muricatum, is the one exception to the 20 year maximum age. (Choat and Bellwood, 1998; Choat and Robertson, 2002)


Parrotfishes are most well known for their complex social structures. Most are organized into male-dominated harems but others breed cooperatively or in pairs (see Reproduction: Mating Systems & General Behavior for more on social systems). Some parrotfishes are highly territorial while others are mainly nomadic, with the home range increasing as the size of the fish increases. Large foraging groups of up to 500 individuals form for spawning and to deter predators while feeding. Parrotfishes feed continuously throughout the day and seek shelter in reefs at night. (Böhlke and Chaplin, 1994; Thresher, 1984)

Communication and Perception

Most known forms of communication in parrotfishes are related to reproduction and are discussed in Reproduction: Mating Systems. However, in some species male coloration intensifies when defending its territory, which suggests that visual cues are used to deter invaders. (Thresher, 1984)

Food Habits

Parrotfishes are primarily herbivorous, grazing intensively on dead, algae-coated coral, vegetable material, and in some species sea grasses. Bump-headed parrotfishes, which consume significant amounts of live coral, are one exception. Key to the success of parrotfishes is their ability to take up plant material, detritus and calcareous sediment and process it through the action of the pharyngeal jaw. This chewing mechanism grinds ingested material into a fine paste and breaks down algal cells, releasing the cellular material for digestion. Like acanthurids, parrotfishes form large feeding groups, sometimes with multiple species, to overwhelm territorial fishes and deter predators. (Choat and Bellwood, 1998; Thresher, 1984)


A unique feature of some parrotfishes is the production of a mucous envelope at night before resting. The envelope takes about 30 minutes to construct and is open at both ends to allow water flow. The secreted envelope is foul smelling and tasting, which may serve to deter nighttime predators that hunt by scent. Most parrotfishes seek out caves and ledges in the reef for protection at night, but parrotfishes in the genus Cryptotomus bury themselves in the sand like wrasses. After creating a hole in the sand Cryptotomus then produces its mucous nightgown. (Böhlke and Chaplin, 1994; Choat and Bellwood, 1998; Nelson, 1994)

Ecosystem Roles

Parrotfishes have a major impact on coral reefs through intensive grazing and associated bioerosion. The grazing patterns of large schools of parrotfish have the effect of selecting for certain species of corals and algae, and preventing algae from choking out corals. Many parrotfishes feed on calcareous algae (algae that are high in mineral calcium) growing on dead, exposed coral by biting off chunks and turning them into a fine paste. This type of grazing contributes significantly to the process of bioerosion and the creation of sediment on reefs. For instance, it has been calculated that a single large parrotfish, Bolbometapon muricatum (bump-head parrotfish), consumes approximately one cubic meter of coral skeletons per year, and turns it into fine sediment. In this way large schools of bump-head parrotfish determine the fine-scale topography of coral reefs. (Choat and Bellwood, 1998)

A separate ecological consequence of intense herbivory in parrotfishes is the conversion of plant material into fish flesh. The success of parrotfishes in consuming plant material unavailable to most other fishes and the large size of parrotfish populations makes them an important part of the predatory food chain. (Choat and Bellwood, 1998)

Economic Importance for Humans: Positive

In the Bahamas, the scales of some parrotfishes are used for decorating basketwork and shellflower arrangements, but the fish are not consumed. In other areas, parrotfishes are sometimes taken as food, but their flesh can be dangerous to humans as a result of accumulated ciguatera toxins. (Böhlke and Chaplin, 1994)

  • Positive Impacts
  • food
  • body parts are source of valuable material
  • research and education

Economic Importance for Humans: Negative

Several species, such as blue parrotfish and one Indo-Pacific species, have caused ciguatera (fish poisoning sickness) in humans, which can be fatal. (Böhlke and Chaplin, 1994)

  • Negative Impacts
  • injures humans

Conservation Status

One scarid, Scarus guacamaia (rainbow parrotfish), is listed as vulnerable to extinction. (The World Conservation Union, 2002)

  • IUCN Red List [Link]
    Not Evaluated

Other Comments

The fossil history of scarids dates back to the lower Tertiary and Eocene epochs. (Berg, 1958)


R. Jamil Jonna (author), Animal Diversity Web.


Atlantic Ocean


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Pacific Ocean


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bilateral symmetry



helps break down and decompose dead plants and/or animals


uses smells or other chemicals to communicate


the nearshore aquatic habitats near a coast, or shoreline.



dominance hierarchies




external fertilization

fertilization takes place outside the female's body


union of egg and spermatozoan




An animal that eats mainly plants or parts of plants.




having the capacity to move from one place to another.


specialized for swimming

native range




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having more than one female as a mate at one time





saltwater or marine


seasonal breeding

breeding is confined to a particular season



sexual ornamentation



associates with others of its species; forms social groups.


uses touch to communicate




uses sight to communicate

year-round breeding

breeding takes place throughout the year




Choat, H., D. Bellwood. 1998. Wrasses & Parrotfishes. Pp. 209-210 in W Eschmeyer, J Paxton, eds. Encyclopedia of Fishes – second edition. San Diego, CA: Academic Press.

Choat, J., D. Robertson. 2002. Age-Based Studies. Pp. 63-67 in P Sale, ed. Coral Reef Fishes: Dynamics and Diversity in a Complex Ecosystem. San Diego, CA: Academic Press.




