Singleline Gemfish, Promethichthys prometheus Cuvier 1832

Other Names: Conejo, Roudi Escolar, Single-line Gemfish

A Singleline Gemfish, Promethichthys prometheus, collected during the 2003 NORFANZ Expedition to survey seamount chains in the Tasman Sea. Source: NORFANZ Founding Parties. License: All rights reserved


Little is known about the biology of the Singleline Gemfish. Its common name is derived from the single lateral line.

Cite this page as:
Schultz, S., Promethichthys prometheus in Fishes of Australia, accessed 17 Jun 2024,

Singleline Gemfish, Promethichthys prometheus Cuvier 1832

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Cosmopolitan distribution, found in all tropical and warm-temperate waters. In Australia restricted to east coast, between the Coral Sea (off QLD) to the Clarence River (NSW). An oceanic species, benthopelgaic, found at depths of 100 to 750 m.


D XVII-XVIII, 0, I, 17-20; A II-III, 15-17; P 13-15.

Pelvic fins reduced to tiny single spine in juveniles, absent in adults. Second dorsal and anal fins followed by two finlets. Body moderately elongate and compressed. Body depth 6.5-7.0 times into standard length. Head length 3.5-3.7 times into standard length. Lower jaw protrudes, both jaws without dermal processes. Three or four pairs of rigid, and 0-3 pairs of depressible fang-like teeth in upper jaw. One pair of fang-like teeth in lower jaw. Vomerine teeth absent, palatine teeth present. Lateral line single, originates above gill cover, descends sharply to below sixth first dorsal fin spine to midbody, then runs horizontally to the caudal fin origin. Entire body scaled in specimens larger than 25 cm (SL).


To at least 100 cm.


Body grey to copper brown. Fins black in fish larger than 40 cm (SL), yellowish with black tips in smaller specimens. First dorsal fin with black spot on membranes between first two fin rays. Buccal and branchial cavities black. 


Feeds on fishes, cephalopods and crustaceans.


Probably spawns throughout the year in tropical waters.


Of no interest to fisheries.



Species Citation

Gempylus prometheus Cuvier 1832, Historie naturelle des poissons. 8: 213, Pl. 222, St. Helena Island, South Atlantic.


Schultz, S.

Singleline Gemfish, Promethichthys prometheus Cuvier 1832


Carpenter, K.E.; Niem, V.H. (eds). FAO species identification guide for fishery purposes. The living marine resources of the Western Central Pacific. Volume 6. Bony fishes part 4 (Labridae to Latimeriidae), estuarine crocodiles, sea turtles, sea snakes and marine mammals. Rome, FAO. 2001. pp. 3381-4218.

Hoese, D.F., D.J. Bray, J.R. Paxton, & G.R. Allen. 2006. Fishes. in Beesley, P.L. & A. Wells. (eds) Zoological Catalogue of Australia. Volume 35. ABRS & CSIRO Publishing: Australia. parts 1-3, pages 1-2178.

Nakamura, I. and N. V. Parin. FAO species catalogue. Vol. 15. Snake mackerels and cutlassfishes of the world (Families Gempylidae and Trichiuridae). An annotated and illustrated catalogue of the snake mackerels, snoeks, escolars, gemfishes, sackfishes, domine, oilfish,cutlassfishes, scabbardfishes, hairtails, and frostfishes known to date. FAO Fisheries Synopis. No. 125, Vol. 15. 1993. 136 p., 200 figs.

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CAAB Code:37439013

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