Netfin grouper (Epinephelus miliaris)

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Netfin grouper fact file

Netfin grouper description

GenusEpinephelus (1)

A fairly large and commercially valuable reef fish, the netfin grouper (Epinephelus miliaris) has a dense pattern of small, yellowish-brown spots covering the head and body, and large, blackish-brown spots adorning the fins. Between four and five bars are often visible on the body, which is generally elongated and rather robust (2) (3) (4). Like all grouper species, netfin grouper young are characterised by a kite-shaped body, with greatly elongated spines on the dorsal and pelvic fins (4).

Also known as
netfin rockcod.
Epinephelus dictyophorus, Epinephelus diktiophorus, Epinephelus fuscus, Epinephelus gaimardi, Serranus diktiophorus, Serranus gaimardi, Serranus miliaris.
Merou Abielle, Vielle Abielle, Vielle Fou-fou.
Mero Colmenar.
Length: up to 50 cm (2)

Netfin grouper biology

Like other members of the genus Epinephelus, the netfin grouper is a major predator in the coral reef ecosystem, thought to feed mainly on fish and large invertebrates, such as crustaceans, on or near the sea bottom (1) (4). Most grouper species are ambush predators, hiding amongst rocks and coral waiting for suitable prey to pass by. All species in this genus appear to display protogynous hermaphroditism, an unusual reproductive strategy in which individuals begin mature life as female and change sex later to become male (4). Most species of grouper produce large numbers of eggs each year, often (but not always) aggregating in large groups to spawn (5).


Netfin grouper range

Distributed throughout the Indo-Pacific region, the netfin grouper is found from East Africa (excluding the Red Sea and Arabian Gulf) and throughout the Indian Ocean, to the Gilbert Islands and Samoa in the Pacific Ocean (1) (3).


Netfin grouper habitat

The netfin grouper is generally found on coral or rocky reefs, at depths of 10 to 200 metres. Juveniles of the netfin grouper are also found in a variety of other habitats, including mud bottoms, sea grass beds and in mangrove swamps (1) (4).


Netfin grouper status

The netfin grouper is classified as Least Concern (LC) on the IUCN Red List (1).

IUCN Red List species status – Least Concern


Netfin grouper threats

Although not currently considered threatened, it is recognised that the netfin grouper is being increasingly impacted by overfishing and habitat destruction (1).


Netfin grouper conservation

While there are no specific conservation measures in place for the netfin grouper, this species does occur in some Marine Protected Areas across its range (1).

ARKive is supported by OTEP, a joint programme of funding from the UK FCO and DFID which provides support to address priority environmental issues in the Overseas Territories, and Defra

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Diverse group of arthropods (a phylum of animals with jointed limbs and a hard chitinous exoskeleton) characterised by the possession of two pairs of antennae, one pair of mandibles (parts of the mouthparts used for handling and processing food) and two pairs of maxillae (appendages used in eating, which are located behind the mandibles). Includes crabs, lobsters, shrimps, slaters, woodlice and barnacles.
Dorsal fin
The unpaired fin found on the back of the body of fish, or the raised structure on the back of most cetaceans.
Animals with no backbone, such as insects, crustaceans, worms, molluscs, spiders, cnidarians (jellyfish, corals, sea anemones), echinoderms, and others.
Pelvic fins
In fish, the pair of fins found on the underside of the body.
Protogynous hermaphroditism
A system in which an animal begins its life cycle as a female, but as it ages, based on internal or external triggers, it shifts sex to become a male animal.
The production or depositing of large quantities of eggs in water.


  1. IUCN Red List (September, 2010)
  2. Rome, B.M. and Newman, S.J. (2010) North Coast Fish Identification Guide. Department of Fisheries, Perth, Australia.
  3. Fish Base (September, 2010)
  4. Heemstra, P.C. and Randall, J.E. (1993) FAO Species Catalogue. Vol. 16: Groupers of the World. Food and Agricultural Organization, Rome. Available at:
  5. Grouper and Wrasse Specialist Group (September, 2010)

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Head profile of netfin grouper  
Head profile of netfin grouper

© Colin Marshall /

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