Blackedged angelfish (Genicanthus watanabei)

Classification (WoRMS)

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

Accepted name: Genicanthus watanabei · Authority: (Yasuda & Tominaga, 1970) · Taxonomic status: accepted · AphiaID: 279099.

Synonyms and superseded combinations recorded for this taxon: Holacanthus watanabei Yasuda & Tominaga, 1970.

Source: World Register of Marine Species (WoRMS) — https://www.marinespecies.org/aphia.php?p=taxdetails&id=279099 (CC BY 4.0). Accessed 2026-09-25.

Biology and life history (FishBase)

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

Maximum length: 15 cm · Depth range: 21–81 m · Habitat zone: reef-associated · Body shape: short and / or deep · Vulnerability index: 10 of 100 · Fishery importance: commercial · Aquarium trade: commercial.

FishBase notes: Occurs in current-swept outer reef slopes and drop-offs (Ref. 4859). Feeds on plankton. Forms harems of 2-5 individuals. Occasionally exported through the aquarium trade (Ref. 48391).

Source: FishBase species summary (SpecCode 8711) — https://www.fishbase.se/summary/Genicanthus-watanabei.html (CC BY-NC 3.0 — non-commercial use only). Accessed 2026-09-25.

Distribution and occurrence records (GBIF)

202 georeferenced occurrence records for Genicanthus watanabei are published through GBIF from 13 countries or marine areas. The map above plots 57 distinct locations from a sample of 202 records, omitting 6 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: New Caledonia (76); Northern Mariana Islands (35); Australia (30); French Polynesia (27); Japan (8); Vanuatu (8); Chinese Taipei (5); Fiji (4); Philippines (3); Cook Islands (2); Marshall Islands (2); Solomon Islands (1); Tonga (1).

Source: GBIF Occurrence Search (taxonKey 2396456) — https://www.gbif.org/occurrence/search?taxon_key=2396456&has_coordinate=true (records CC0 / CC BY); WoRMS distribution records (MarineRegions) — https://www.marinespecies.org/aphia.php?p=taxdetails&id=279099 (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 Genicanthus watanabei (Yasuda & Tominaga, 1970) 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 165872) — https://www.iucnredlist.org/species/165872/0; GBIF IUCN Red List category endpoint (taxonKey 2396456) — https://api.gbif.org/v1/species/2396456/iucnRedListCategory. Accessed 2026-09-25.

Description and natural history (Wikipedia)

Genicanthus watanabei, like the other angelfishes in the genus Genicanthus, shows sexual dichromatism, the males and females show differences in colour and pattern. The males are pale blue to bluish-grey on the upper third of their bodies with the lower two thirds having 8 horizontal, thin black stripes, the highest of these end in a patch of yellow colour. The females are overall light blue colour with wide black bars across their head and a black spot on the snout. In both males and females there is a wide submarginal band on the dorsal and anal fins, and on the lobes of the caudal fin.

Juveniles somewhat resemble females in colour. In both sexes the forked tail narrows at its base to create a "swallow tail". The dorsal fin contains 15-16 spines and 15-16 soft rays while the anal fin has 3 spines and 14-17 soft rays. This species attains a maximum total length of 15 cm.

Distribution

Genicanthus watanabei is found in the Pacific Ocean. It ranges from Taiwan east to the Cook Islands and Tuamotu Archipelago, north to the Ryukyu Islands and south to New Caledonia and the Austral Islands. It also occurs on the Great Barrier Reef with juveniles reaching as far south as Sydney.

Habitat and biology

Genicanthus watanabei occurs at depths between 12 and 81 m. Here can be found on the outward slopes of reefs and on drop offs where there is a strong current. It feeds on plankton in the water column. Like all of their congeners the blackedged angelfish is a protogynous hermaphrodite, starting their life as female and the dominant female may change into a male They have a lek mating system.

In a lek, the large males control territories. And the more numerous females are able to move freely between the territories of the males. When the females are receptive to mating the males display to them, swimming on their sides and vibrating their fins. The largest and most dominant males prefer to breed with the younger females.

Systematics

Genicanthus watanabei was first formally described in 1970 by the Japanese ichthyologists Fujio Yasuda and Yoshiaki Tominaga with the type locality given as Onna Beach on Okinawa. The specific name honours the Japanese ichthyologist Masao Watanabe of Waseda University in Tokyo, who originally collected this fish but identified it as Genicanthus caudovittatus.

Utilisation

Genicanthus watanabei is not a frequently traded species in the aquarium trade. Those specimens which do enter the trade mostly come from the Philippines and from Melanesia.

Source: Wikipedia: Genicanthus watanabei — https://en.wikipedia.org/wiki/Genicanthus_watanabei (CC BY-SA 4.0). Accessed 2026-09-25.