Blotched foxface (Siganus unimaculatus)

Classification (WoRMS)

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

Accepted name: Siganus unimaculatus · Authority: (Evermann & Seale, 1907) · Taxonomic status: accepted · AphiaID: 273925.

Synonyms and superseded combinations recorded for this taxon: Lo unimaculatus Evermann & Seale, 1907.

Source: World Register of Marine Species (WoRMS) — https://www.marinespecies.org/aphia.php?p=taxdetails&id=273925 (CC BY 4.0). Accessed 2026-09-25.

Biology and life history (FishBase)

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

Maximum length: 20 cm · Habitat zone: reef-associated · Body shape: short and / or deep · Vulnerability index: 14.4 of 100 · Fishery importance: commercial · Aquarium trade: commercial.

FishBase notes: Inhabits rich coral areas of lagoons and outer reefs, often among staghorn corals (Ref. 90102). Small juveniles occur in schools of up to a few hundred fish, larger juveniles and adults occur in pairs. Feeds on seaweeds (Ref. 9813).

Source: FishBase species summary (SpecCode 4630) — https://www.fishbase.se/summary/Siganus-unimaculatus.html (CC BY-NC 3.0 — non-commercial use only). Accessed 2026-09-25.

Distribution and occurrence records (GBIF)

111 georeferenced occurrence records for Siganus unimaculatus are published through GBIF from 6 countries or marine areas. The map above plots 25 distinct locations from a sample of 111 records, omitting 4 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: Japan (61); Philippines (45); Singapore (2); Egypt (1); Malaysia (1); Chinese Taipei (1).

Marine regions with a valid WoRMS distribution record: Chinese Exclusive Economic Zone.

Source: GBIF Occurrence Search (taxonKey 2390313) — https://www.gbif.org/occurrence/search?taxon_key=2390313&has_coordinate=true (records CC0 / CC BY); WoRMS distribution records (MarineRegions) — https://www.marinespecies.org/aphia.php?p=taxdetails&id=273925 (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 unimaculatus (Evermann & Seale, 1907) as Data Deficient (code DD). 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 141484154) — https://www.iucnredlist.org/species/141484154/0; GBIF IUCN Red List category endpoint (taxonKey 2390313) — https://api.gbif.org/v1/species/2390313/iucnRedListCategory. Accessed 2026-09-25.

Description and natural history (Wikipedia)

The blotched foxace was first formally described in 1907 as Lo unimaculatus by the American ichthyologists Barton Warren Evermann and Alvin Seale with the type locality given as "Bacon, Sorsogon, east coast of southern Luzon Island, Philippines". This species differs from the foxface rabbitfish (S. vulpinus) in possessing a large black spot below the soft-rayed part of the dorsal fin. It is sympatric and not phylogenetically distinct, and though these two might be recently evolved species, they may be just colour morphs and should arguably to be united under the scientific name S. vulpinus. The specific name is a compound of uni which means "one" and maculatus meaning "spotted", a reference to the characteristic black spot.

Description

The blotched foxface has a compressed body which has a depth which fits into its standard length 1.9 times. The dorsal profile of the head is steep to the rearof the eye and there is an indentation between the eyes. The caudal fin is forked. Like all rabbitfishes, the dorsal fin has 13 spines and 10 soft rays while the anal fin has 7 spines and 9 soft rays.

The fin spines hold venom glands. This species attains a maximum total length of 20 cm. This species is bright yellow with the head and front part of the body being white with a black band running from the mouth to the start of the dorsal fin and another black band extending from the shoulder to the chest. There is an irregular black spot or blotch on the centre to rear of the upper flanks.

Distribution and habitat

The blotched foxface has two disjunct populations: a northern population which is found in the Western Pacific Ocean from the Ryukyu and Ogasawara Islands of Japan to the Philippines, and a southern population which is restricted to the Rowley Shoals in the Timor Sea off northwestern Australia. This species is found in shallow waters down to 14 m on coral reefs made up of Acropora and Porites, and also on coral rubble.

Biology

The blotched foxface is herbivorous and feeds on seaweeds. Adults an subadults live in pairs, including same-sex pairs; the adult pairs seem to be permanent. Reproduction appears to takes place at the new moon when large aggregations occur and the demersal eggs are laid.

Juveniles may gather in large schools. This species produces venom in the spines of its fins. In a study of the venom of a congener it was found that rabbitfish venom was similar to the venom of stonefishes.

Utilisation

The blotched foxface is targeted by fisheries using spearfishing and drive-in nets, the catch being sold for food. They also appear in the aquarium trade.

Source: Wikipedia: Blotched foxface — https://en.wikipedia.org/wiki/Blotched_foxface (CC BY-SA 4.0). Accessed 2026-09-25.