Black hamlet (Hypoplectrus nigricans)

Classification (WoRMS)

Full classification as recorded by WoRMS: Kingdom: Animalia · Phylum: Chordata · Class: Teleostei · Order: Perciformes · Family: Serranidae · Genus: Hypoplectrus.

Accepted name: Hypoplectrus nigricans · Authority: (Poey, 1852) · Taxonomic status: accepted · AphiaID: 281118.

Synonyms and superseded combinations recorded for this taxon: Plectropoma nigricans Poey, 1852.

Source: World Register of Marine Species (WoRMS) — https://www.marinespecies.org/aphia.php?p=taxdetails&id=281118 (CC BY 4.0). Accessed 2026-09-25.

Biology and life history (FishBase)

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

Maximum length: 15.239999771118164 cm · Depth range: 3–13 m · Habitat zone: reef-associated · Body shape: short and / or deep · Vulnerability index: 10 of 100 · Fishery importance: commercial · Aquarium trade: commercial.

FishBase notes: A solitary species (Ref. 26340) inhabiting shallow reefs (Ref. 9710). Feeds on fishes and crustaceans (Ref. 26180). Often found near the bottom around soft and hard corals. Occasionally been seen spawning with the H. chlorurus (Ref. 26938)

Source: FishBase species summary (SpecCode 16535) — https://www.fishbase.se/summary/Hypoplectrus-nigricans.html (CC BY-NC 3.0 — non-commercial use only). Accessed 2026-09-25.

Distribution and occurrence records (GBIF)

22,253 georeferenced occurrence records for Hypoplectrus nigricans are published through GBIF from 25 countries or marine areas. The map above plots 61 distinct locations from a sample of 3,000 records, omitting 10 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 of America (18,912); Puerto Rico (2,383); Virgin Islands (U.S.) (596); Mexico (82); Colombia (55).

The full country table, WoRMS marine regions and the sampling notes are on this species' Distribution page.

Source: GBIF Occurrence Search (taxonKey 2388786) — https://www.gbif.org/occurrence/search?taxon_key=2388786&has_coordinate=true (records CC0 / CC BY); WoRMS distribution records (MarineRegions) — https://www.marinespecies.org/aphia.php?p=taxdetails&id=281118 (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 Hypoplectrus nigricans (Poey, 1852) 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 16759111) — https://www.iucnredlist.org/species/16759111/0; GBIF IUCN Red List category endpoint (taxonKey 2388786) — https://api.gbif.org/v1/species/2388786/iucnRedListCategory. Accessed 2026-09-25.

Description and natural history (Wikipedia)

Hypoplectrus nigricans is a small fish growing to a total length of 85 to 150 mm. The morphology and colouring of the fish varies across its range. Fish from Puerto Rico have greyish bodies, translucent pectoral fins, pointed pelvic fins and a caudal fin shaped like a crescent moon. Fish from Mexico and Belize are slightly smaller and have a darker body colour with dark pectoral fins, blunt pelvic fins and a short, square-cut caudal fin.

The species is native to the central West Atlantic Ocean. Its range extends from southeastern Florida and the Bahamas, through the Caribbean Sea and the Gulf of Mexico to Santa Marta in Colombia and to the islands off the coast of Venezuela. It is a reef fish, inhabiting reefs with both stony corals and soft corals.

As a simultaneous hermaphrodite, H. nigricans has an unusual reproductive strategy known as egg trading. The fish is usually solitary, but at breeding time two fish come together at night. Courtship is initiated by one fish which temporarily takes a female role. The other fish acts as the male and fertilises a batch of eggs produced by the first fish.

The following night their roles are reversed, and the second fish lays eggs and the first fish fertilises them. The two fish continue alternating roles in this way over the course of several nights. The pair usually stay together for the series of transfers, but sometimes each finds a different partner.

H. nigricans has a wide range and is a common fish. No particular threats have been identified and its population seems to be steady, so the International Union for Conservation of Nature has assessed its conservation status as being of "least concern".

Source: Wikipedia: Hypoplectrus nigricans — https://en.wikipedia.org/wiki/Hypoplectrus_nigricans (CC BY-SA 4.0). Accessed 2026-09-25.