Ctenochaetus striatus
A widespread surgeonfish with blue lines and orange head spots.
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Ctenochaetus striatus, commonly known as the striated surgeonfish, lined bristletooth, fine-lined bristletooth, or striped bristletooth, is a species of marine ray-finned fish belonging to the family Acanthuridae, which includes surgeonfishes, unicornfishes, and tangs. It has a wide Indo-Pacific distribution and is notable for its role in the food chain of ciguatera poisoning.
Scientific classification
- KingdomAnimalia
- PhylumChordata
- ClassActinopterygii
- DivisionTeleostei
- OrderAcanthuriformes
- FamilyAcanthuridae
- GenusCtenochaetus
- SpeciesCtenochaetus striatus
Named by (Quoy & Gaimard, 1825)
Close relatives
Other species of Ctenochaetus with a Codexery entry.
- Ctenochaetus binotatus Ctenochaetus binotatus
- Ctenochaetus flavicauda Ctenochaetus flavicauda
- Ctenochaetus hawaiiensis Ctenochaetus hawaiiensis
- Ctenochaetus marginatus Ctenochaetus marginatus
- Ctenochaetus strigosus Ctenochaetus strigosus
Sources: Wikipedia taxobox: Ctenochaetus striatus (CC BY-SA 4.0) · order, family and genus agree with WoRMS AphiaID 219659 (CC BY 4.0)
Conservation status
Least Concern (LC)
- LC▲ this species
- NT
- VU
- EN
- CR
- EW
- EX
Source: IUCN Red List assessment · GBIF copy of the Red List category
How big is it?
Largest length in the source, 0.26 m, next to a 1.8 m person.
Diagram: drawn by Codexery, schematic shapes to scale (not a likeness). Length: Wikipedia: Ctenochaetus striatus
Lore & Background
Ctenochaetus striatus was first formally described as Acanthurus striatus in 1825 by the French naturalists Jean René Constant Quoy and Joseph Paul Gaimard, with its type locality given as Guam in the Marianas Islands. The genera Ctenochaetus and Acanthurus make up the tribe Acanthurini, one of three tribes in the subfamily Acanthurinae within the family Acanthuridae. The specific name striatus means 'furrowed' or 'grooved', or in other words 'striped', alluding to the many longitudinal stripes created by the edges of the scale rows that extend onto the dorsal and anal fin bases.
The overall colour is greenish-brown with slender, sinuous blue lines along the flanks and many orange spots on the head; the blue lines continue on the dorsal and anal fins. Juveniles have a different appearance. This species is found on reef flats, lagoon reefs, and seaward reefs over coral, rock pavement, and rubble at depths between 0 and 60 m. Its range extends across the Indian and Pacific Oceans from the coast of eastern Africa, from the Red Sea south to Aliwal Shoal off South Africa, across the Indian Ocean (though not on the mainland coast of South Asia between the Gulf of Oman and the Bay of Bengal), and into the Pacific Ocean east to Pitcairn Island and French Polynesia, north to the Ryukyu Islands of southern Japan, and south to Rapa Iti and the Elizabeth and Middleton Reefs in the Coral Sea.
Taxonomic Heritage & the Meaning of Its Name
Ctenochaetus striatus entered the scientific record in 1825 when two French naturalists, Jean René Constant Quoy and Joseph Paul Gaimard, formally described the species under the name Acanthurus striatus, designating Guam in the Marianas Islands as the type locality. Over time the species was reassigned to the genus Ctenochaetus, which together with Acanthurus forms the tribe Acanthurini. This tribe sits within the subfamily Acanthurinae, one of just two subfamilies recognized in the broader family Acanthuridae, which encompasses surgeonfishes, unicornfishes, and tangs.
The specific epithet striatus derives from the Latin for "furrowed" or "grooved," a direct reference to the numerous longitudinal stripes produced by the edges of the scale rows. These stripes are so prominent that they extend beyond the body onto the bases of both the dorsal and anal fins. The fish is known by several common names—striated surgeonfish, lined bristletooth, fine-lined bristletooth, and striped bristletooth—each capturing the same distinctive lined appearance that gives the species its scientific name.
A Palette of Green, Blue, and Orange
The adult striated surgeonfish presents a strikingly patterned body that reaches a maximum published total length of 26 centimeters, roughly ten inches. Its base coloration is a muted greenish-brown, overlaid with slender, sinuous blue lines that trace the flanks in a wavy pattern. These same blue markings continue seamlessly onto the dorsal and anal fins, creating a visual continuity between body and finnage. The head is dotted with numerous small orange spots, adding a warm contrast to the cooler tones elsewhere.
Structurally, the dorsal fin is supported by eight spines and a count of 27 to 31 soft rays, while the anal fin carries three spines alongside 24 to 28 soft rays. The combination of the striped flank pattern, the orange-spotted head, and the blue-tinged fins makes this species immediately recognizable among the many surgeonfishes inhabiting Indo-Pacific reefs. The fine, grooved lines that inspired its Latin name are the most defining visual feature, running longitudinally along the body and giving the fish its "lined" or "striped" common names.
A Vast Indo-Pacific Range
The striated surgeonfish enjoys one of the broadest distributions among reef-associated surgeonfishes, spanning both the Indian and Pacific Oceans. In the Indian Ocean, its range stretches from the Red Sea along the eastern African coast southward to Aliwal Shoal off South Africa. Moving across the Indian Ocean basin, the species is notably absent from the mainland coast of South Asia between the Gulf of Oman and the Bay of Bengal, a gap that sets its distribution apart from some congeners.
In the Pacific, populations extend eastward to Pitcairn Island and the waters of French Polynesia, northward to the Ryukyu Islands off southern Japan, and southward to Rapa Iti as well as the Elizabeth and Middleton Reefs in the Coral Sea. Within this enormous range, the fish occupies reef flats, lagoon reefs, and seaward reefs, preferring substrates of living coral, rock pavement, and rubble. It is found at depths ranging from the surface down to 60 meters, making it a species of both shallow and moderately deep reef environments.
Feeding, Spawning, and a Role in Human Health
In daily life the striated surgeonfish may be seen alone, in modest groups, or in very large mixed-species schools. Its diet centers on grazing the thin surface film of blue-green algae and diatoms, supplemented by various small invertebrates. This herbivorous role places the species as a key link in the food chain underlying ciguatera poisoning, a condition that can affect humans through the marine food web. Research in Rarotonga has shown that when Pacific cyclones disturb reef habitats, populations of herbivorous fish like the striated surgeonfish increase, and with them the risk of ciguatera cases rises; conversely, fewer cyclones correlate with fewer poisoning incidents.
Reproductively, spawning is tightly synchronized with the full moon. Large aggregations form, and individuals sit motionless in the water column for one to three hours, shifting their coloration to grey. Then a small number of fish rise toward the surface, circle one another, and discharge milt and eggs. In the larval stage the species displays a unique behavioral trait: unlike most coral-fish larvae that are repelled by or selectively drawn to particular sounds, striated surgeonfish larvae show a non-selective attraction to noisy areas.
Reader's Guide
Ctenochaetus striatus is encountered solitarily or in small to very large, frequently mixed-species schools. It grazes on the surface film of blue-green algae and diatoms, as well as various small invertebrates. This species is a key link in the food chain of ciguatera; it has been found that the incidence of ciguatera poisoning in Rarotonga decreased as the frequency of Pacific cyclones decreased. Cyclones disturb the reef, resulting in increased populations of herbivorous fishes such as the striated surgeonfish and a greater risk of humans suffering ciguatera poisoning.
Spawning is linked to the full moon, and these fishes gather in large aggregations to spawn. The fish sit still in the water for between 1 and 3 hours, changing colour to grey before a handful of fishes rise toward the surface and circle around each other, discharging milt and eggs. When compared to other coral-fish larvae, the striated surgeonfish uniquely exhibits a non-selective attraction to noisy areas, where others are repelled or are selectively attracted to specific sounds. The species is targeted as a food fish using traps and nets and is also captured for the aquarium trade.
More in Reef Aquarium Fish Species
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Sources
Compiled from Wikipedia and the sources listed below. Text from Wikipedia is available under CC BY-SA 4.0; this entry is adapted from it.
- Wikipedia: Ctenochaetus striatus (CC BY-SA 4.0).
- Classification: the source article's taxobox; order, family and genus checked against WoRMS, the World Register of Marine Species (CC BY 4.0).
- Conservation status: IUCN Red List assessment.
- Word definitions: the Codexery glossary, each quoted from its Wikipedia article.
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