Halfnaked Hatchetfish, Argyropelecus hemigymnus Cocco 1829
Other Names: Axefish, Half-naked Hatchetfish, Half-naked Hatchet-fish
Halfnaked Hatchetfish, Argyropelecus hemigymnus. Source: Australian National Fish Collection, CSIRO. License: CC BY Attribution-Noncommercial
Summary:
A small hatchetfish
Cite this page as:
Bray, D.J. 2025, Argyropelecus hemigymnus in Fishes of Australia, accessed 19 Jul 2026, https://fishesofaustralia.net.au/Home/species/3940
Halfnaked Hatchetfish, Argyropelecus hemigymnus Cocco 1829
More Info
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Distribution |
A bathypelagic species, found at depths of up to 2,400 m. Usually occurs at 200-700 m during the day - concentrating at 350-550 m. At night, found at 100-650 m, preferring 150-380 m. Adults make daily vertical migrations to feed in shallower waters at night. |
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Features |
Dorsal fin 8; Anal fin 11; Pectoral fin 10-11; Gill rakers (total) 18-24; Vertebrae 36-38. VAV and AC photophores on lower side of body behind pelvic fin distinctly not in a straight line, noticeably separated into groups; no distinct gaps separating ACC photophores posterior to anal fin. |
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Size |
A small species, 5.1 cm TL. |
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Feeding |
Adults undertake daily vertical migrations in the water column, rising at dusk to feed on copepods and small fishes in shallower waters. |
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Biology |
The photophores of Argyropelecus are thought to luminesce continuously (Clarke, 1963), with the intensity of the light produced being rapidly adjusted and modulated to match that of the background twilight. Females spawn planktonic eggs multiple times during a season. |
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Remarks |
Adult Halfnaked Hatchetfish undertake daily vertical migrations, rising in the water column at dusk to feed on copepods and small fishes in shallower mesopelagic and epipelagic waters. |
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Similar Species |
Differs from other species of Argyropelecus in its small size, in having a narrow trunk, a single post-abdominal spine, minute teeth, and the presence of 8 dorsal-fin rays and 11 anal-fin rays. |
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Species Citation |
Argyropelecus hemigymnus Cocco 1829, Giornale di Scienze, Lettere ed Arti per la Sicilia (Palermo) 7 26(77): 146. Type locality: Messina. |
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Author |
Bray, D.J. 2025 |
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Resources |
Halfnaked Hatchetfish, Argyropelecus hemigymnus Cocco 1829
References
Cocco, A. 1829. Su di alcuni pesci de'mari di Messina. Giornale di Scienze, Lettere ed Arti per la Sicilia (Palermo) 7 26(77): 138-147
Gon, O. 1990. Sternoptychidae, pp. 123-126 in Gon, O. & Heemstra, P.C. (eds). Fishes of the Southern Ocean. Grahamstown, South Africa : J.L.B. Smith Institute of Ichthyology, 462 pp.
Harold, A.S. 1999. Families Gonostomatidae, Sternoptychidae, Phosichthyidae, Astronesthidae, Stomiidae, Chauliodontidae, Melanostomiidae, Idiacanthidae, Malacosteidae. pp. 1896-1917 in Carpenter, K.E. & Niem, V.H. (eds). The Living Marine Resources of the Western Central Pacific. FAO Species Identification Guide for Fisheries Purposes. Rome : FAO Vol. 3 pp. 1397-2068.
Harold, A.S. 2010. Argyropelecus hemigymnus. In: IUCN 2014. IUCN Red List of Threatened Species. Version 2014.1.
Hopkins, T.L., Sutton, T.T. & Lancraft, T.M. 1996. The trophic structure and predation impact of a low latitude midwater fish assemblage. Progress in Oceanography 38: 205-239.
