Diamond Trevally, Scyris indica Rüppell 1830

Other Names: Diamond Fish, Diamond-fish, High-brow Pennantfish, Indian Mirrorfish, Indian Threadfin, Indian Threadfish, Mirror Fish, Mirror-fish, Plumed Trevally, Threadfin Trevally

A Diamond Trevally, Scyris indica, from Mexico. Source: Gary Bulla / FishBase. License: CC BY Attribution-NonCommercial


Adults have an angular, strongly compressed body, whereas young fish are almost diamond-shaped. Juveniles have extremely long filaments trailing from their dorsal, anal and pelvic fins - and they appear to mimic box jellyfish. The filaments gradually reduce as the fish grows and are absent in adult Diamond Trevally.

This species was previously known as Alectis indica.

Video of juvenile Diamond Trevally, also known as Indian Threadfish.

Cite this page as:
Bray, D.J. 2022, Scyris indica in Fishes of Australia, accessed 28 May 2024, https://fishesofaustralia.net.au/home/species/4254

Diamond Trevally, Scyris indica Rüppell 1830

More Info


Houtman Abrolhos, Western A
ustralia, around the tropical north to Wollongong, New South Wales; also at Christmas Island in the eastern Indian Ocean. Elsewhere, the species is widespread in the Indo-West Pacific, from the Red Sea and East Africa to French Polynesia, north to southern Japan and south to northern Australia.

Adults are pelagic around reefs, while juveniles occur in a range of habitats, including estuaries and seagrass beds.


Feeds on a range of fishes, small squids, and crustaceans.


Of minor commercial importance in parts of its range, and a popular sports fish. the species is also aquacultured in Southeast Asia.


Prior to the publication of Kimura et al. (2022), this species was known as Alectis indica.

Similar Species

Similar to the closely related Pennantfish, Alectis ciliaris, that also has long trailing filaments on the dorsal and anal fins. Juvenile Pennantfish, however, lack elongate filaments on the pelvic fins. Adult Pennantfish have a more rounded head profile, versus the more angular head profile of the Diamond Trevally.


Species Citation

Scyris indicus Rüppell 1830, Fische des Rothen Meeres: 128, pl. 33(1). Type locality: Jidda, Saudi Arabia (as Djedda), Red Sea.


Bray, D.J. 2022


Atlas of Living Australia

Diamond Trevally, Scyris indica Rüppell 1830


Allen, G.R. 1997. Marine Fishes of Tropical Australia and South-east Asia. Perth : Western Australian Museum 292 pp. 106 pls. (as Alectis indica)

Allen, G.R. & Erdmann, M.V. 2012. Reef fishes of the East Indies. Perth : Tropical Reef Research 3 vols, 1260 pp. (as Alectis indica)

Allen, G.R., Steene, R.C. & Orchard, M. 2007. Fishes of Christmas Island. Christmas Island : Christmas Island Natural History Association 2 edn, 284 pp. (as Alectis indica)

Blaber, S.J.M. & Cyrus, D.P. 1983. The biology of Carangidae (Teleostei) in Natal estuaries. Journal of Fish Biology 22(2): 173-188. (as Alectis indica)

Grant, E.M. 1975. Guide to Fishes. Brisbane : Queensland Government, Co-ordinator General’s Department 640 pp. (as Alectis indica)

Grant, E.M. 2002. Guide to Fishes. Redcliffe : EM Grant Pty Ltd 880 pp. (as Alectis indica)

Gunn, J.S. 1990. A revision of selected genera of the family Carangidae (Pisces) from Australian waters. Records of the Australian Museum, Supplement 12: 1-77 (as Alectis indica)

Hobbs, J.-P.A., Newman, S.J., Mitsopoulos, G.E.A., Travers, M.J., Skepper, C.L., Gilligan, J.J., Allen, G.A., Choat, H.J. & Ayling, A.M. 2014. Checklist and new records of Christmas Island fishes: the influence of isolation, biogeography and habitat availability on species abundance and community composition. Raffles Bulletin of Zoology 30: 184-202.

Hutchins, J.B. & Swainston, R. 1986. Sea Fishes of Southern Australia. Complete field guide for anglers and divers. Perth : Swainston Publishing 180 pp. (as Alectis indica)

Johnson, J.W. 2010. Fishes of the Moreton Bay Marine Park and adjacent continental shelf waters, Queensland, Australia. pp. 299-353 in Davie, P.J.F. & Phillips, J.A. Proceedings of the Thirteenth International Marine Biological Workshop, The Marine Fauna and Flora of Moreton Bay. Memoirs of the Queensland Museum 54(3) (as Alectis indica)

Kimura, S., Takeuchi, S. & Yadome, T. 2022. Generic revision of the species formerly belonging to the genus Carangoides and its related genera (Carangiformes: Carangidae). Ichthyological Research. https://doi.org/10.1007/s10228-021-00850-1

Kuiter, R.H. 1993. Coastal Fishes of South-eastern Australia. Bathurst : Crawford House Press 437 pp. (as Alectis indica)

Larson, H.K., Williams, R.S. & Hammer, M.P. 2013. An annotated checklist of the fishes of the Northern Territory, Australia. Zootaxa 3696(1): 1-293

Randall, J.E., Allen, G.R. & Steene, R. 1990. Fishes of the Great Barrier Reef and Coral Sea. Bathurst : Crawford House Press 507 pp. figs. (as Alectis indica)

Randall, J.E., Allen, G.R. & Steene, R. 1997. Fishes of the Great Barrier Reef and Coral Sea. Bathurst : Crawford House Press 557 pp. figs. (as Alectis indica)

Roughley, T.C. 1957. Fish and Fisheries of Australia. Sydney : Angus & Robertson 341 pp. (as Alectis indica)

Rüppell, W.P.E. 1830. Atlas zu der Reise im nördlichen Afrika. Fische des Rothen Meeres. 3. Frankfurt : H.L. Brünner 95-141 pls 25-35.

Russell, B.C. & Houston, W. 1989. Offshore fishes of the Arafura Sea. The Beagle 6(1): 69-84. (as Alectis indica)

Sainsbury, K.J., Kailola, P.J. & Leyland, G.G. 1985. Continental Shelf Fishes of Northern and North-Western Australia. Canberra : Fisheries Information Service 375 pp. figs & pls. (as Alectis indica)

Smith-Vaniz, W.F. 1999. Family Carangidae. pp. 2659-2756 in Carpenter, K.E. & Niem, T.H. (eds). The Living Marine Resources of the Western Central Pacific. FAO Species Identification Guide for Fisheries Purposes. Rome : FAO Vol. 4 2069-2790 pp. (as Alectis indica)

Smith-Vaniz, W.F. & Williams, I. 2016. Alectis indica (errata version published in 2017). The IUCN Red List of Threatened Species 2016: e.T20253300A115370143. https://dx.doi.org/10.2305/IUCN.UK.2016-3.RLTS.T20253300A46664019.en. Accessed on 01 August 2022.

von Westernhagen, H. 1974. Observations on the natural spawning of Alectis indicus (Rüppell) and Caranx ignobilis (Forsk.) (Carangidae). Journal of Fish Biology 6(4): 513–516. https://doi.org/10.1111/j.1095-8649.1974.tb04567.x

Quick Facts

CAAB Code:37337038

Conservation:IUCN Least Concern

Depth:to 100 m

Fishing:Sports fish

Habitat:Pelagic, reef associated

Max Size:165 cm TL

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