Blackcheek moray eel (Gymnothorax breedeni)
Source-cited species reference: taxonomy from WoRMS, biology from FishBase, occurrence map from GBIF, conservation from IUCN Red List, description from Wikipedia.
The blackcheek moray eel or masked moray (Gymnothorax breedeni) is a species of marine fish in the family Muraenidae.
- Scientific name
- Gymnothorax breedeni
- Authority
- McCosker & Randall, 1977
- Family
- Muraenidae
- Order
- Anguilliformes
- Maximum length
- 100 cm
- Depth range
- 4–40 m
- Habitat zone
- reef-associated
- Iucn red list
- Least Concern
- Gbif occurrence records
- 304
Classification (WoRMS)
Full classification as recorded by WoRMS: Kingdom: Animalia · Phylum: Chordata · Class: Teleostei · Order: Anguilliformes · Family: Muraenidae · Genus: Gymnothorax.
Accepted name: Gymnothorax breedeni · Authority: McCosker & Randall, 1977 · Taxonomic status: accepted · AphiaID: 217480.
Source: World Register of Marine Species (WoRMS) — https://www.marinespecies.org/aphia.php?p=taxdetails&id=217480 (CC BY 4.0). Accessed 2026-09-23.
Biology and life history (FishBase)
Measured values published by FishBase for Gymnothorax breedeni. Only fields the database actually holds for this species are shown; these are database values, not aquarium guidance.
Maximum length: 100 cm · Depth range: 4–40 m · Habitat zone: reef-associated · Body shape: eel-like · Vulnerability index: 60 of 100 · Fishery importance: minor commercial · Aquarium trade: never/rarely.
FishBase notes: Inhabits clear seaward reefs of oceanic islands to a depth over 25 m (Ref. 9710). Common on reef walls and steep slopes with holes (Ref. 30404). Inhabits porous coral rock which it shares with swarms of anthiases (Ref. 37816). Feeds on fishes and octopi (Ref. 89972). Territorial and will bite when provoked (Ref. 30404). Minimum depth reported taken from Ref. 9710.
Source: FishBase species summary (SpecCode 7881) — https://www.fishbase.se/summary/Gymnothorax-breedeni.html (CC BY-NC 3.0 — non-commercial use only). Accessed 2026-09-23.
Distribution and occurrence records (GBIF)
304 georeferenced occurrence records for Gymnothorax breedeni are published through GBIF from 22 countries or marine areas. The map above plots 52 distinct locations from a sample of 304 records, omitting 2 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: United States Minor Outlying Islands (155); Maldives (32); South Africa (23); Madagascar (15); French Polynesia (15); Christmas Island (12); Mozambique (12); Tanzania, United Republic of (7); Kiribati (5); Seychelles (5); Mayotte (4); Micronesia (Federated States of) (3); Japan (3); Papua New Guinea (3); French Southern Territories (3).
Marine regions with a valid WoRMS distribution record: Comoran Exclusive Economic Zone; Seychellois Exclusive Economic Zone; Chagos; South Africa (country); Mozambican Exclusive Economic Zone.
Source: GBIF Occurrence Search (taxonKey 2403813) — https://www.gbif.org/occurrence/search?taxon_key=2403813&has_coordinate=true (records CC0 / CC BY); WoRMS distribution records (MarineRegions) — https://www.marinespecies.org/aphia.php?p=taxdetails&id=217480 (CC BY 4.0); Natural Earth 110m basemap — https://www.naturalearthdata.com/ (public domain). Accessed 2026-09-23.
Conservation status (IUCN Red List)
The IUCN Red List assesses Gymnothorax breedeni McCosker & Randall, 1977 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 195712) — https://www.iucnredlist.org/species/195712/0; GBIF IUCN Red List category endpoint (taxonKey 2403813) — https://api.gbif.org/v1/species/2403813/iucnRedListCategory. Accessed 2026-09-23.
Description and natural history (Wikipedia)
The blackcheek moray eel is widespread throughout the tropical waters of the Indo-Pacific area from eastern coast of Africa until oceanic islands from the Pacific Ocean like Polynesia but not Hawaii. It is a very common moray on the Maldives reefs.
This moray eel occurs in clear seaward reefs of oceanic islands, especially in porous coral rock and in reef walls and steep slopes with holes. It likes reefs composed of rubble and debris of dead coral in which it finds its shelter, often on the outer slopes between 4 and 40 meters deep.
The blackcheek moray eel is a medium-sized fish that can reach a maximum length of 100 cm, but usually morays observed are often smaller. The background body color is brown speckled in a relatively high density with darker spots. This moray is easily identifiable by the large irregular black patch mark (hence the common name of blackcheek moray eel) starting from the eye and finishing in the corner of the mouth. Otherwise, its anal orifice and its gills aperture are black.
The blackcheek moray is rather solitary and very territorial, it is likely to bite any foreign body entering its vigilance area.
It also lives in association with cleaner shrimps and the Anthias. It feeds on fish and octopuses at night, when it comes out of its lair.
Source: Wikipedia: Blackcheek moray eel — https://en.wikipedia.org/wiki/Blackcheek_moray_eel (CC BY-SA 4.0). Accessed 2026-09-23.
Frequently Asked Questions
What is the Blackcheek moray eel (Gymnothorax breedeni)?
It is a species of marine moray eel in the family Muraenidae, also commonly called the masked moray. The species was formally described by McCosker and Randall in 1977.
How big does the Blackcheek moray eel (Gymnothorax breedeni) grow?
This eel reaches a maximum total length of roughly 100 centimeters, placing it in the mid-sized range among its Gymnothorax relatives.
Where does the Blackcheek moray eel (Gymnothorax breedeni) live?
It occupies saltwater habitats at depths between about 4 and 40 meters below the surface. As a member of the order Anguilliformes, it is a fully marine, elongated-bodied fish.
How is the Blackcheek moray eel (Gymnothorax breedeni) classified taxonomically?
It belongs to the genus Gymnothorax within the family Muraenidae and the order Anguilliformes. Its binomial name, Gymnothorax breedeni, was established by McCosker and Randall in 1977.
Why is the Blackcheek moray eel (Gymnothorax breedeni) of interest to fish enthusiasts?
It represents one of the many Gymnothorax species that make the moray eel family one of the most speciose groups of marine predators. Its relatively shallow depth range (4–40 m) and modest 100 cm maximum size distinguish it from larger, deeper-dwelling congeners.
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