The acanthurids (surgeonfishes and unicornfishes) are a speciose family of coral reef fishes that occur worldwide in tropical and subtropical latitudes. They are highly abundant on reef systems and are perhaps the most ecologically impactful herbivores on many reef systems. However, not all species are herbivorous – some groups instead specialise in feeding on plankton or detritus. They are popular aquarium fishes, but their large size, highly active behaviour, and often, territoriality, means they require a large tank. One defining feature of the group is the presence of large specialised scales on the caudal peduncle that form sharp blades, used for predator defense and warding off rivals. In some species, these blades are known to be venomous. For this thread I will be going by iNaturalist’s taxonomy for this family, which recognises 85 species in 6 genera. Nearly half of these species are in the highly diverse Acanthurus.
N.B. – The words ‘surgeonfish’ and ‘tang’ are used interchangeably in many species names, and are effectively synonymous.
Genus Acanthurus – 42 species
Achilles Tang A. achilles
Whitechin Surgeonfish A. albimento
Whitefin Surgeonfish A. albipectoralis
Orange-socket Surgeonfish A. auranticavus
Brazilian Ocean (Barber) Surgeonfish A. bahianus
Eyespot Surgeonfish A. bariene
Dark Surgeonfish A. blochii
Doctorfish A. chirurgus
Chronixis (Kapingamarangi) Surgeonfish A. chronixis
Atlantic Blue Tang A. coeruleus
Pencil Surgeonfish A. dussumieri
Horseshoe (Fowler’s) Surgeonfish A. fowleri
Black Surgeonfish A. gahhm
Inshore Surgeonfish A. grammoptilus
Whitespotted Surgeonfish A. guttatus
Japan Surgeonfish A. japonicus
White-spine (Palelipped) Surgeonfish A. leucocheilus
Whitebar Surgeonfish A. leucopareius
Powder Blue Tang A. leucosternon
Bluelined (Clown) Surgeonfish A. lineatus
Spotted-face Surgeonfish A maculiceps
Pale (Elongate) Surgeonfish A. mata
Mindoro Surgeonfish A. mindorensis
Monrovia Doctorfish A. monroviae
Velvet (Whitecheek) Surgeonfish A. nigricans
Eyeline (Epaulette) Surgeonfish A. nigricauda
Dusky Surgeonfish (Lavender Tang) A. nigrofuscus
Hawaiian Blueline Surgeonfish A. nigroris
Greyhead Surgeonfish A. nigros
Bluelined (Pinstriped) Surgeonfish A. nubilus
Orangeblotch (Orangeshoulder) Surgeonfish A. olivaceus
Black-barred Surgeonfish (Zebra Tang) A. polyzona
Pacific Mimic (Chocolate) Tang A. pyroferus
Marquesian Surgeonfish A. reversus
Hawaiian Convict Tang (Manini) A. sandvicensis
Sohal (Red Sea) Surgeonfish A. sohal
Lieutenant (Doubleband) Surgeonfish A. tennentii
Night (Thompson’s) Surgeonfish A. thompsoni
Caribbean Ocean (Five-band) Surgeonfish A. tractus
Convict Tang A. triostegus
Indian Ocean Mimic Tang A. tristis
Yellowmask Surgeonfish A. xanthopterus
Genus Ctenochaetus – 9 species
Twospot Bristletooth C. binotatus
Yellowspot Bristletooth C. cyanocheilus
Whitetail Bristletooth C. flavicauda
Hawaiian Bristletooth (Chevron Tang) C. hawaiiensis
Blue-spotted Bristletooth C. marginatus
Lined Bristletooth C. striatus
Goldring Surgeonfish (Kole Tang) C. strigosus
Orange-tip Bristletooth (Tomini Tang) C. tominiensis
Indian Goldring Bristletooth C. truncatus
Genus Naso – 20 species
Ringtail Unicornfish N. annulatus
Humpback Unicornfish N. brachycentron
Paletail (Spotted) Unicornfish N. brevirostris
Blue Unicornfish N. caeruleacauda
Grey Unicornfish N. caesius
Elegant Unicornfish (Blonde Naso Tang) N. elegans
Horseface Unicornfish N. fageni
Sleek Unicornfish N. hexacanthus
Pacific Orange-spined Unicornfish (Naso Tang) N. lituratus
Slender Unicornfish N. lopezi
Scribbled Unicornfish N. maculatus
Squarenose Unicornfish N. mcdadei
Blackspine Unicornfish N. minor
Reticulate Unicornfish N. reticulatus
Taiwanese Unicornfish N. tergus
Onespot Unicornfish N. thynnoides
Humpnose Unicornfish N. tonganus
Humphead Unicornfish N. tuberosus
Bluespine Unicornfish N. unicornis
Bignose (Vlaming’s) Unicornfish N. vlamingii
Genus Paracanthurus – 1 species
Regal (Palette) Tang – P. hepatus
Genus Prionurus – 6 species
Biafra Doctorfish P. biafraensis
Indonesian Sawtail P. chrysurus
Razor Sawtail (Surgeonfish) P. laticlavius
Spotted Sawtail P. maculatus
Australian Sawtail P. microlepidotus
Scalpel Sawtail P. scalprum
Genus Zebrasoma – 7 species
Indian Sailfin Tang Z. desjardinii
Yellow Tang Z. flavescens
Gem Tang Z. gemmatum
Black Tang Z. rostratum
Brown (Scopas) Tang Z. scopas
Pacific Sailfin Tang Z. velifer
Purple Tang Z. xanthurum
N.B. – The words ‘surgeonfish’ and ‘tang’ are used interchangeably in many species names, and are effectively synonymous.
Genus Acanthurus – 42 species
Achilles Tang A. achilles
Whitechin Surgeonfish A. albimento
Whitefin Surgeonfish A. albipectoralis
Orange-socket Surgeonfish A. auranticavus
Brazilian Ocean (Barber) Surgeonfish A. bahianus
Eyespot Surgeonfish A. bariene
Dark Surgeonfish A. blochii
Doctorfish A. chirurgus
Chronixis (Kapingamarangi) Surgeonfish A. chronixis
Atlantic Blue Tang A. coeruleus
Pencil Surgeonfish A. dussumieri
Horseshoe (Fowler’s) Surgeonfish A. fowleri
Black Surgeonfish A. gahhm
Inshore Surgeonfish A. grammoptilus
Whitespotted Surgeonfish A. guttatus
Japan Surgeonfish A. japonicus
White-spine (Palelipped) Surgeonfish A. leucocheilus
Whitebar Surgeonfish A. leucopareius
Powder Blue Tang A. leucosternon
Bluelined (Clown) Surgeonfish A. lineatus
Spotted-face Surgeonfish A maculiceps
Pale (Elongate) Surgeonfish A. mata
Mindoro Surgeonfish A. mindorensis
Monrovia Doctorfish A. monroviae
Velvet (Whitecheek) Surgeonfish A. nigricans
Eyeline (Epaulette) Surgeonfish A. nigricauda
Dusky Surgeonfish (Lavender Tang) A. nigrofuscus
Hawaiian Blueline Surgeonfish A. nigroris
Greyhead Surgeonfish A. nigros
Bluelined (Pinstriped) Surgeonfish A. nubilus
Orangeblotch (Orangeshoulder) Surgeonfish A. olivaceus
Black-barred Surgeonfish (Zebra Tang) A. polyzona
Pacific Mimic (Chocolate) Tang A. pyroferus
Marquesian Surgeonfish A. reversus
Hawaiian Convict Tang (Manini) A. sandvicensis
Sohal (Red Sea) Surgeonfish A. sohal
Lieutenant (Doubleband) Surgeonfish A. tennentii
Night (Thompson’s) Surgeonfish A. thompsoni
Caribbean Ocean (Five-band) Surgeonfish A. tractus
Convict Tang A. triostegus
Indian Ocean Mimic Tang A. tristis
Yellowmask Surgeonfish A. xanthopterus
Genus Ctenochaetus – 9 species
Twospot Bristletooth C. binotatus
Yellowspot Bristletooth C. cyanocheilus
Whitetail Bristletooth C. flavicauda
Hawaiian Bristletooth (Chevron Tang) C. hawaiiensis
Blue-spotted Bristletooth C. marginatus
Lined Bristletooth C. striatus
Goldring Surgeonfish (Kole Tang) C. strigosus
Orange-tip Bristletooth (Tomini Tang) C. tominiensis
Indian Goldring Bristletooth C. truncatus
Genus Naso – 20 species
Ringtail Unicornfish N. annulatus
Humpback Unicornfish N. brachycentron
Paletail (Spotted) Unicornfish N. brevirostris
Blue Unicornfish N. caeruleacauda
Grey Unicornfish N. caesius
Elegant Unicornfish (Blonde Naso Tang) N. elegans
Horseface Unicornfish N. fageni
Sleek Unicornfish N. hexacanthus
Pacific Orange-spined Unicornfish (Naso Tang) N. lituratus
Slender Unicornfish N. lopezi
Scribbled Unicornfish N. maculatus
Squarenose Unicornfish N. mcdadei
Blackspine Unicornfish N. minor
Reticulate Unicornfish N. reticulatus
Taiwanese Unicornfish N. tergus
Onespot Unicornfish N. thynnoides
Humpnose Unicornfish N. tonganus
Humphead Unicornfish N. tuberosus
Bluespine Unicornfish N. unicornis
Bignose (Vlaming’s) Unicornfish N. vlamingii
Genus Paracanthurus – 1 species
Regal (Palette) Tang – P. hepatus
Genus Prionurus – 6 species
Biafra Doctorfish P. biafraensis
Indonesian Sawtail P. chrysurus
Razor Sawtail (Surgeonfish) P. laticlavius
Spotted Sawtail P. maculatus
Australian Sawtail P. microlepidotus
Scalpel Sawtail P. scalprum
Genus Zebrasoma – 7 species
Indian Sailfin Tang Z. desjardinii
Yellow Tang Z. flavescens
Gem Tang Z. gemmatum
Black Tang Z. rostratum
Brown (Scopas) Tang Z. scopas
Pacific Sailfin Tang Z. velifer
Purple Tang Z. xanthurum








































































