Geometric moray (Gymnothorax griseus)
Source-cited species reference: taxonomy from WoRMS, biology from FishBase, occurrence map from GBIF, conservation from IUCN Red List, description from Wikipedia.
is a moray eel of the family Muraenidae found throughout the western Indian Ocean at depths to 40 m. Its length is up to 65 cm. It is parasitized by Ichthyoxenus puhi, a species of isopod.
- Scientific name
- Gymnothorax griseus
- Authority
- (Lacepède, 1803)
- Family
- Muraenidae
- Order
- Anguilliformes
- Maximum length
- 65 cm
- Depth range
- 1–40 m
- Habitat zone
- reef-associated
- Iucn red list
- Least Concern
- Gbif occurrence records
- 1,004
Classification (WoRMS)
Full classification as recorded by WoRMS: Kingdom: Animalia · Phylum: Chordata · Class: Teleostei · Order: Anguilliformes · Family: Muraenidae · Genus: Gymnothorax.
Accepted name: Gymnothorax griseus · Authority: (Lacepède, 1803) · Taxonomic status: accepted · AphiaID: 271838.
Synonyms and superseded combinations recorded for this taxon: Muraena bilineata Rüppell, 1838; Muraena geometrica Rüppell, 1830; Muraenophis grisea Lacepède, 1803; Siderea grisea (Lacepède, 1803); Siderea schonlandi Smith, 1949.
Source: World Register of Marine Species (WoRMS) — https://www.marinespecies.org/aphia.php?p=taxdetails&id=271838 (CC BY 4.0). Accessed 2026-09-23.
Biology and life history (FishBase)
Measured values published by FishBase for Gymnothorax griseus. Only fields the database actually holds for this species are shown; these are database values, not aquarium guidance.
Maximum length: 65 cm · Depth range: 1–40 m · Habitat zone: reef-associated · Body shape: eel-like · Vulnerability index: 46 of 100 · Fishery importance: minor commercial · Aquarium trade: never/rarely.
FishBase notes: Found in shallow coastal waters, on coral and rocky reefs (Ref. 30573). Simultaneous hermaphroditism is confirmed for this species (Ref. 103751).
Source: FishBase species summary (SpecCode 8058) — https://www.fishbase.se/summary/Gymnothorax-griseus.html (CC BY-NC 3.0 — non-commercial use only). Accessed 2026-09-23.
Distribution and occurrence records (GBIF)
1,004 georeferenced occurrence records for Gymnothorax griseus are published through GBIF from 28 countries or marine areas. The map above plots 132 distinct locations from a sample of 1,004 records, omitting 27 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: Egypt (290); Mauritius (84); South Africa (80); Seychelles (76); Australia (71).
The full country table, WoRMS marine regions and the sampling notes are on this species' Distribution page.
Source: GBIF Occurrence Search (taxonKey 2404095) — https://www.gbif.org/occurrence/search?taxon_key=2404095&has_coordinate=true (records CC0 / CC BY); WoRMS distribution records (MarineRegions) — https://www.marinespecies.org/aphia.php?p=taxdetails&id=271838 (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 griseus (Lacepède, 1803) 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 195734) — https://www.iucnredlist.org/species/195734/0; GBIF IUCN Red List category endpoint (taxonKey 2404095) — https://api.gbif.org/v1/species/2404095/iucnRedListCategory. Accessed 2026-09-23.
Description and natural history (Wikipedia)
The fish is generally pale purple, white or brownish in colour, with a greyish head with distinct lines of black dots.
The geometric moray is a species of moray. The moray family (Muraenidae) is divided into two subfamilies: the snakemorays (subfamily:Uropterygiinae) and the typical morays (subfamily:Muraeninae). This species is classified within the latter due to having a dorsal fin in parts of the body where they wouldn't be in snakemorays. Within the subfamily, G. griseus is classified within the genus Gymnothorax, which contains over half of the species in the family.
This species' closest relative is the white-eyed moray (Gymnothorax thyrsoideus), which shares the common feature of white eyes; and also is not found in most places that G. griseus is in. The next closest relative to these two is Castle's moray (Gymnothorax castlei), which shares features with this species, such as having an almost identical pattern of spots, and having dots on the lateral line (griseus sometimes has the latter feature). More distant relatives include the False and Arabian false brown morays (Gymnothorax pseudoherrei & G. arabicus, respectively) and the Mottled moray (Echidna delicauta).
Source: Wikipedia: Geometric moray — https://en.wikipedia.org/wiki/Geometric_moray (CC BY-SA 4.0). Accessed 2026-09-23.
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