These are also primarily herbivorous fishes, and some are coralivorous (eat corals).  They are important for the reef habitat because they eat algae.  Algae, when it grows too abundantly, inhibits coral growth.  When the reef loses its structure, it loses habitat for other fishes and invertebrates.

Click the arrow symbol under each fish for more information.

Bolbometopon muricatum, Green Humphead Parrotfish

    • Vulnerable species on the IUCN Red List
    • Max length 130 cm, common length 70 cm, max published weight 46 kg
    • Sometimes confused with the humphead wrasse.  Unlike the wrasse, it has a vertical head profile.  Unlike other parrotfishes, it is uniformly covered except in the leading edge of the head, which is often light green to pink, and has a nodular outer surface to its beak.  Primary phase is a dull gray with scattered white spots, gradually becoming a dark green
    • Usually found in small groups in outer lagoons and seaward reefs, depth 1-30m
    • Feeds on benthic algae, live corals and shellfishes, possibly rams its head against corals to facilitate feeding
    • Sleeps in caves or shipwrecks at night
    • Vulnerable to overfishing, high to very high vulnerability
    • Low resilience, minimum population doubling time 4.5 – 14 years

Cetoscarus bicolor, Bicolour Parrotfish

    • Max length 90 cm
    • Clear lagoons and seaward reefs, Depth range 1 – 30m
    • Juveniles usually solitary; adults form harems.  Males are territorial
    • Several changes in appearance during growth, very large females change sex to the very brightly colored male
    • Small juveniles usually stay in dense coral and algae habitats
    • Benthic grazer of algae
    • Medium resilience, medium population doubling time 1.4 – 4.4 years

Chlorurus frontalis, Pacific Slopehead Parrotfish

    • Max length 50 cm, common length 38 cm
    • Depth range up to 40m
    • Coloration changes slowly with growth. Light green patch on caudal peduncle is present on individuals as small as 15 cm and the tan facial markings are on most individuals greater than 20 cm
    • Large males develop a near-vertical forehead profile and long lobes and a well-developed lunate caudal fin
    • Often seen in small schools on exposed reef flats and seaward reefs
    • Medium resilience, minimum population doubling time 1.4 – 4.4 years

Chlorurus microrhinos, Steephead Parrotfish

    • Max length 70 cm, common length 49 cm (male), 40 cm (female)
    • Juveniles below 8 cm black w/several horizontal white stripes
    • Larger juveniles up to 20 cm are uniformly dark, greenish brown, slowly becoming blue with age
    • Blue streak and patch extending behind corner of the mouth of large males often quite brilliant
    • Males develop a large hump on head and appear blunt-headed
    • Found in lagoons and seaward reefs. Depth range 1-35m
    • Juveniles are generally solitary; large adults often school together
    • Reports of ciguatera poisoning
    • Low resilience, minimum population doubling time 4.5 – 14 years. Vulnerable

Chlorurus sordidus, Bullethead Parrotfish

    • Max length 40 cm
    • Variable in coloration. Small individuals may be dark brown to light gray and may have dark-centered light area on the caudal peduncle; large fish may have series of irregular rows of small light spots posteriorly, or have dark centered area on caudal peduncle. Terminal phase also variable may have a large tan area on the side or on caudal peduncle. Rounded snout
    • Marine, brackish. Inhabit both coral rich and open pavement areas of reef flats and lagoons and seaward reefs as well as drop-offs, exhibit different behavior in various areas. Depth range up to 50m
    • Juveniles in large groups that migrate great distances between feeding and sleeping grounds
    • Feeds on benthic algae
    • Medium resilience, minimum population doubling time 1.4 – 4.4 years. Potentially vulnerable

Hipposcarus longiceps, Pacific Longnose Parrotfish

    • Max length 60 cm, common length 48 cm
    • Small juveniles are light brownish with a broad longitudinal orange band; primary phase is whitish brown to light gray with a yellowish tail. Terminal phase is light blue and green. Adults are best recognized by the shape of the head
    • Inhabits turbid lagoons more than reef areas, reef associated; up to 40m depth
    • Usually seen in aggregations; females in small groups
    • Listed as Least Concern on
      IUCN Red List
    • High resilience, minimum population doubling time less than 15 months

Scarus altipinnis, Filament-finned Parrotfish

    • Only Scarus in which one of the middle dorsal rays of terminal males is produced into a slightly elongate filament
    • Small juveniles have distinctive yellow head and striped-to-mottled body
    • Adults usually seen along the reef margin of seaward reefs while juveniles and subadults are found in shallow protected reefs. Reef associated to 50m depth
    • Feeds mainly on algae, seen in groups
    • Medium resilience, minimum population doubling time 1.4 – 4.4 years. Potentially vulnerable

Scarus frenatus, Bridled Parrotfish

    • Max length 47 cm, max reported age 20 years
    • Usually found on exposed outer reefs, sometimes in very shallow water. Depth range 3 – 20m
    • Juveniles occur among coral and rubble of lagoon reefs
    • Grazes on benthic algae
    • Generally solitary, often in school of mixed species while feeding
    • Medium resilience, minimum population doubling time 1.4 – 4.4 years. Low vulnerability

Scarus ghobban, Blue-barred Parrotfish

    • Max length 90 cm, common length 30 cm, max reported age 13 years
    • Distinctive yellow and blue-barred primary phase
    • Adults inhabit lagoon and seaward reefs, in slopes and drop-offs, often solitary but ma sometimes occur in small groups. Depth range 3 – 36 m
    • Males common in atolls where they live mainly around the inner and outer edges of barrier reefs at depths of about 30 ft, females prefer deeper habitat
    • Small juvenile groups are found inshore on algae reef habitat and sometimes enter silty, murky environments
    • Feed by scraping algae from rocks and corals
    • Low resilience, minimum population doubling time 4.5 – 14 years. Moderate vulnerability

Scarus globiceps, Globehead Parrotfish

    • Common length 45 cm
    • Primary phase difficult to distinguish from S. psittacus and S. rivulatus. S. globiceps differs in that it is the only one with 3 scale rows and 5 more scales in the ventral row
    • More common in outer reef habitats than in protected waters. Spawns in groups or pairs
    • Depth range up to 12 m
    • High resilience, minimum population doubling time less than 15 months. Low vulnerability

Scarus oviceps, Egghead Parrotfish

    • Max length 35 cm
    • Males recognized by dark area over head and body, and females yellow barring
    • Closely resembes S. dimidiatus, but differs in that its initial phase has fewer, less vertical diagonal black bars on the back and the terminal phase lacks the light centered bar between the eye and pectoral fin base, is darker and less blue on the upper head and back and is usually larger
    • Inhabits lagoon and seaward reefs to at least 10 m
    • Occurs singly
    • High resilience, minimum population doubling time less than 15 months. Low to moderate vulnerability

Scarus psittacus, Palenose Parrotfish

    • Maximum length to 30 cm, max age to 5 years
    • The initial phase closely resembles that of S. globiceps and S. rivulatus. May be differed according to the number of scale rows and scales on the ventral side
    • Inhabit reef flats and lagoon and seaward reefs to at least 25 m depth. Found over corals. Initial-phase fish stage usually form small feeding schools. Graze on benthic algae
    • High resilience, minimum population doubling time less than 15 months. Low Vulnerability

Scarus rubroviolaceus, Ember Parrotfish

    • Max length 70 cm, max reported age 20 years
    • Depth range 1 – 36 m
    • Occurs in seaward reefs. Usually over rocky or coral substrates, at boulder strewn slopes at the base of the high-island cliffs where it may occur in large schools
    • Large adults usually on upper parts of deep slopes, but seen to about 35 m depth
    • Bethopelagic
    • Feeds on benthic algae
    • A protogynous hermaphrodite; Born female and change sex to male later in life
    • Uncommon species
    • Species of least concern on IUCN Red List
    • Medium resilience, minimum population doubling time 1.4 – 4.4 years
    • Moderate to high vulnerability

Scarus schlegeli, Yellowband Parrotfish

    • Max length 40 cm (male), 30 cm (female)
    • Large scales, Caudal fin slightly rounded in initial phase, retained in terminal males with protruding lobes. Lips cover or nearly cover dental plates. Initial phase no canines; terminal males usually 1 upper canine and 2 on lower
    • Initial phase characterized by a series of irregular dark chevrons; may be hard to see on dark individuals
    • Basic color may range from pale gray to a deep mahogany
    • Inhabits lagoon and seaward reefs. Adults common in areas with rich coral and high vertical relief
    • Juveniles may school with other species
    • Feeding aggregations on rubble and mixed rubble-coral slopes rather than on flats. Depth range 1 – 50 m
    • Males exhibit territorial tendencies
    • Medium resilience, minimum population doubling time 1.4 – 4.4 years. Moderate vulnerability