Royal Gemfish, Rexea prometheoides (Bleeker 1856)

Other Names: Prometheus Gemfish, Royal Escolar

Little is known about the biology of the Royal Gemfish.

Cite this page as:
Schultz, S., Rexea prometheoides in Fishes of Australia, accessed 17 Aug 2022,

Royal Gemfish, Rexea prometheoides (Bleeker 1856)

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from 135 to 540 m


Indo-west Pacific distribution. In northern Australian waters it is known to occur between Shark Bay (WA) and Cooloangatta (QLD), though it is absent from the Gulf of Carpentaria. An oceanic species, bentho- and mesopelagic, found at depths of 135 to 540 m.


D XVIII-XIX, 0, 1, 14-17; A II, 12-15; P 12-14.

Pelvic fins reduced to tiny single spine in juveniles, absent in adults. Second dorsal and anal fins followed by two finlets. Body elongate and compressed. Body depth 5-6 times into standard length. Head length 3.1-3.4 times into standard length. Lower jaw protrudes, both jaws without dermal processes. Five or six pairs of fang-like teeth in upper jaw. One pair of fang-like teeth in lower jaw. Lateral line bifurcated below fourth to fifth first dorsal fin spine, the upper lateral line reaches middle to end of second dorsal fin base, lower lateral line midlateral to caudal fin origin. Body naked, except for a large stripe of tiny scales extending forward from caudal peduncle to below middle of first dorsal fin base.


To at least 40 cm.


Body greyish with silvery tint. Fins hyaline except first dorsal fin with black spot on first fin membrane, second dorsal fin black or grey.






Of no interest to fisheries.



Species Citation

Thyrsites prometheoides Bleeker1856, Acta Societatis Regiae Scientiarum Indo-Neêrlandicae 1: 42, Ambon Island, Moluccas Islands, Indonesia [as Amboina].


Schultz, S.

Royal Gemfish, Rexea prometheoides (Bleeker 1856)


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.

Quick Facts

CAAB Code:37439006

Species Maps

CAAB distribution map