Streamlined spinefoot (Siganus argenteus)

Classification (WoRMS)

Full classification as recorded by WoRMS: Kingdom: Animalia · Phylum: Chordata · Class: Teleostei · Order: Acanthuriformes · Family: Siganidae · Genus: Siganus.

Accepted name: Siganus argenteus · Authority: (Quoy & Gaimard, 1825) · Taxonomic status: accepted · AphiaID: 219686.

Synonyms and superseded combinations recorded for this taxon: Amphacanthus argenteus Quoy & Gaimard, 1825; Amphacanthus mertensii Valenciennes, 1835; Amphacanthus rostratus Valenciennes, 1835; Siganas rostrata (Valenciennes, 1835); Siganus argebteys (Quoy & Gaimard, 1825); Siganus rostratus (Valenciennes, 1835); Siganus vitianus (Sauvage, 1882); Teuthis argentea (Quoy & Gaimard, 1825); Teuthis oligosticta Kner, 1868; Teuthis rostrata (Valenciennes, 1835); Teuthis rostratus (Valenciennes, 1835); Teuthis rostrytus (Valenciennes, 1835); Teuthis vitianus Sauvage, 1882.

Source: World Register of Marine Species (WoRMS) — https://www.marinespecies.org/aphia.php?p=taxdetails&id=219686 (CC BY 4.0). Accessed 2026-09-25.

Biology and life history (FishBase)

Measured values published by FishBase for Siganus argenteus. Only fields the database actually holds for this species are shown; these are database values, not aquarium guidance.

Maximum length: 40 cm · Common length: 25 cm · Depth range: 0–40 m · Habitat zone: reef-associated · Body shape: fusiform / normal · Vulnerability index: 22.2 of 100 · Fishery importance: commercial · Aquarium trade: commercial.

FishBase notes: Inhabits coastal and inner reef slopes and lagoons. Usually occurs in large schools that swim fast and well above the substrate, occasionally all diving down to the bottom to feed (Ref. 48637). Juveniles and adults occur in small schools (2-100) around coral reefs, typically in surge zone at reef edge.

Juveniles live near the surface in dense aggregations up to several km offshore, migrating to reef flats just prior to metamorphosis. Feeds on algae (Ref. 30573). Juveniles and adults not frequently found in markets; but prejuveniles form a brief but important fishery when migrating on to the reef flat, e.g. combined catch (with Siganus spinus of 16 tonnes in one season in Guam.

Prejuveniles eaten fresh, pickled in brine or made into fish paste (Ref. 9813). Consumed as food although it is known to be occasionally poisonous (Ref. 4537). Used in Chinese medicine (Ref. 12166).

Source: FishBase species summary (SpecCode 4614) — https://www.fishbase.se/summary/Siganus-argenteus.html (CC BY-NC 3.0 — non-commercial use only). Accessed 2026-09-25.

Distribution and occurrence records (GBIF)

3,425 georeferenced occurrence records for Siganus argenteus are published through GBIF from 51 countries or marine areas. The map above plots 300 distinct locations from a sample of 3,000 records, omitting 17 inland records that carry an institution's coordinates rather than a collection site; it shows where the species has been observed and reported, not a modelled range.

Most records by country or area: Australia (1,143); Marshall Islands (435); French Polynesia (279); Japan (265); Tonga (209).

The full country table, WoRMS marine regions and the sampling notes are on this species' Distribution page.

Source: GBIF Occurrence Search (taxonKey 2390180) — https://www.gbif.org/occurrence/search?taxon_key=2390180&has_coordinate=true (records CC0 / CC BY); WoRMS distribution records (MarineRegions) — https://www.marinespecies.org/aphia.php?p=taxdetails&id=219686 (CC BY 4.0); Natural Earth 110m basemap — https://www.naturalearthdata.com/ (public domain). Accessed 2026-09-25.

Conservation status (IUCN Red List)

The IUCN Red List assesses Siganus argenteus (Quoy & Gaimard, 1825) as Least Concern (code LC). No trend, population estimate or threat analysis is given here, because none is available from this source without the Red List API; follow the source link for the full assessment, including its date.

Source: IUCN Red List of Threatened Species (taxon 69689070) — https://www.iucnredlist.org/species/69689070/0; GBIF IUCN Red List category endpoint (taxonKey 2390180) — https://api.gbif.org/v1/species/2390180/iucnRedListCategory. Accessed 2026-09-25.

Description and natural history (Wikipedia)

The streamlined spinefoot was first formally described in 1825 as Amphacanthus argenteus by the French naturalists Jean René Constant Quoy and Joseph Paul Gaimard with the type locality given as Guam in the Marianas. The specific name argenteus means "silvery", a reference to the silver colour of the cheeks and lower body.

Description

The streamlined spinefoot has a body which is oval, compressed, slender and fusiform, the body has a standard length which is 2.4 to 3 times its depth. The small head does not have a steep dorsal profile byt has a pointed snout. The front nostril has a flap which extends past the rear nostril. There is a procumbent spine at the front of the dorsal fin which is enclosed in the skin of the nape.

The dorsal fin contains 13 spines and 10 soft rays while the anal fin has 7 spines and 9 soft rays. The caudal fin has a deep fork. This species attains a maximum total length of 40 cm, although 25 cm is more typical. The colours of this species are that blue on the upper body with a silvery lower body.

They frequently have variable markings, spots and curved lines, particularly on the lower flanks. The eye has a silvery-yellow iris. The axil of pectoral fin is yellow and there is normally a yellow stripe along the base of the dorsal fin. There is also a dark brown bar on the upper edge of the operculum.

This fish changes colour when alarmed or asleep to pale and dark brown mottling, with dark areas forming 7 diagonal zones across the flanks and the fins becoming mottled.

Distribution and habitat

The streamlined spinefoot has a wide Indo-Pacific distribution from the Red Sea south to Mozambique and Madagascar and east into the Pacific Ocean as far as Pitcairn Island, north to Japan and south to Australia. In Australia it is distributed from the area of Shark Bay in Western Australia to the Ashmore Reef in the Timor Sea, and on the east coast from the northern Great Barrier Reef near Cape York south to Moreton Bay in Queensland, it also occurs on reefs in the Coral Sea and at the Cocos (Keeling) Islands.

It has been recorded once in the Mediterranean Sea off Libya but how this specimen reached there is uncertain. At remote islands such as Rapa, Pitcairn and the Line Islands this species may be the only rabbitfish present. It occurs at depths down to 40 m in lagoons, on reefs, and in seaweed and seagrass beds.

Biology

The streamlined spinefoot is normally found in large, fast swimming schools on the water column clear of the seabed, every now and again they all dive down to the substrare to feed. Juveniles and adults may be encountered in small schools of 2–100 individuals near coral reefs, usually in the surge zone on the edge of the reef.

Juveniles inhabit the water close to the surface in dense schools as far as several kilometres offshore, moving on to reef flats just before metamorphosis. The streamlined spinefoot has a diet made up of red and green macroalgae and it is one of the few herbivorous fishes that is able to eat the chemically rich macroalgae Chlorodesmis fastigata, however, this algae may only be eaten opportunistically and is likely a minor part of the total diet. They have spines which can inject venom into an attacker.

Unusually for a rabbitfish, the streamlined spinefoot is a pelagic spawner and has a relatively long larval stage and a unique prejuvenile stage. These long developmental stages allow it to disperse widely and make the species less vulnerable than its congeners to overfishing.

Fisheries

Streamlined spinefoot are frequently recorded in markets in parts of their range, both as juveniles and adults. The pre-juveniles are taken as they migrate to reef flat areas in a brief but important part of local fisheries, e.g. in Guam. They are consumed fresh, pickled in brine, or made into fish paste.

Source: Wikipedia: Streamlined spinefoot — https://en.wikipedia.org/wiki/Streamlined_spinefoot (CC BY-SA 4.0). Accessed 2026-09-25.