Welch's Grunter, Bidyanus welchi (McCulloch & Waite 1917)

Other Names: Black Bream, Silver Bream

Welch's Grunter, Bidyanus welchi. Source: Douglass F. Hoese. License: All rights reserved


A greyish-brown to olive-brown robust grunter becoming silvery below, with darker scale margins, and a small head and mouth.

Although this medium to large-sized grunter is similar to the Silver Perch, the two species occur in different drainage systems.

Cite this page as:
Gomon, M.F. & Bray, D.J. 2022, Bidyanus welchi in Fishes of Australia, accessed 20 Jun 2024, https://fishesofaustralia.net.au/home/species/688

Welch's Grunter, Bidyanus welchi (McCulloch & Waite 1917)

More Info


Endemic to internal drainage systems of central Australia including Barcoo River (145º08´E), Diamantina River (139º21´E) and Georgina River (138º15´E), QLD and Lake Eyre drainage, SA (137º00´E), but not recorded from the Northern Territory..
Inhabits turbid areas of larger turbid rivers and permanent waterholes. The species is tolerant to high temperatures and salinities. 


Dorsal fin D XII,11-12; Anal III,8-9; 
Pectoral fin 16-17; Pelvic I,5; Gill rakers 8-9 + 1 + 14-17; Vertebrae 11+14; Transverse scales 10-12/1/25-27

Body elongate, oblong to ovate, slender, depth 3.1-3.3 in SL, slightly compressed, body width 1.5-1.65 in body depth; dorsal and ventral profiles evenly arched; dorsal profile straight from snout to nape, then convex to dorsal origin, ventral profile evenly arched to ventral insertion, then straight to anus. Head length 3.5-3.8 in SL. Snout elongate, length 3.1-3.3 in HL. Eye width 5.0-6.6 in HL. Interorbital region smooth, flat. Nostrils separated by a distance equal to diameter of posterior nostril. Upper jaw slightly longer than lower; jaw length 3.3-3.65 in HL; gape nearly horizontal; maxillary reaching to vertical through posterior nostril; teeth conic, slightly depressible; outer row enlarged, followed by villiform teeth in bands; no teeth on vomer or palatines. Lacrimal serrate. Preoperculum serrate; serrations largest on angle. Lower opercular spine longer and stronger; reaching nearly to edge of opercular lobe. Cleithrum exposed; serrate along posterior edge; scales on side. Supracleithrum exposed. Posttemporal exposed; serrate along posterior edge.

Scales finely ctenoid; lateral line continuous, smoothly curved; 68-72 scales counted in a series above lateral line; 59-66 scales counted in a series below lateral line; 6-9 scales on caudal; 20-25 predorsal scales to occiput; 2-3 rows of scales in sheath at base of dorsal fin, sheath extending to eighth or ninth dorsal ray; 4 rows of scales in sheath at base of anal fin, sheath extending across base of all rays; cheek scales in 5-7 rows.

Dorsal fin continuous, base 1.8-2.0 in SL; spinous portion arched; first spine very short; fifth or sixth longest, 2.1-2.5 in HL, those following decreasing in length to ultimate; longest dorsal spine longer than longest dorsal ray, 2.9-3.7 in HL; posterior edge of soft dorsal slightly convex. Second anal spine very strong, 2.0-2.3 in HL, longer than third, about twice as long as first, as long as longest anal ray, 1.9-2.2 in HL. Pectoral fins pointed; fifth ray longest. Ventral fins pointed; first ray longest; reaching one-half distance to anus. Caudal fin emarginate.


To 40 cm SL but commonly to 23 cm SL.


Yellowish or brownish overall, slightly darker above; body dusky, each scale with a spot of heavier pigmentation along edge of scale pocket; on caudal peduncle, these join together in some specimens to form irregular longitudinal vermiculations. Median fins with slightly dusky membranes. Caudal fin dusky at base. Pelvic fins slightly dusky. Pectoral fins colorless.


Feeds on on small fishes, shrimps and worms.


Oviparous pelagic spawners that migrate upstream to breed during summer floods. Females spawn pelagic eggs, and the larvae hatch after 30 hours at around 24-28 cm. Little is known of the biology and ecology of this species.


Similar Species

Distinguished from all other terapontids in having depressible but unflattened teeth, 20-25 predorsal scales to the occiput, maximum body width 1.5 -1.7  in body depth, 68-72 scales counted in a series above lateral line, and  59-66  below. 


The species is named after McCulloch's "old friend" Edwin J. Welch, a member of the expedition sent to discover the fate members of the Burke and Wills expedition.

Species Citation

Therapon welchi McCulloch & Waite, 1917, Trans. R. Soc. S. Aust. 41: 472. Type locality: Coopers Creek, near Innamincka, South Australia.


Gomon, M.F. & Bray, D.J. 2022


Atlas of Living Australia

Welch's Grunter, Bidyanus welchi (McCulloch & Waite 1917)


Allen, G.R. 1989. Freshwater Fishes of Australia.  Neptune, New Jersey : T.F.H. Publications 240 pp. pls 1–63.

Allen, G.R., Midgley, S.H. & Allen, M. 2002. Field guide to the freshwater fishes of Australia.  Perth : Western Australian Museum 394 pp..

Davis, A., Unmack, P.J., Pusey, B.J.,  Johnson, J.B. & Pearson, R.G. 2012. Marine-freshwater transitions are associated with the evolution of dietary diversification in terapontid grunters (Teleostei: Terapontidae). Journal of Evolutionary Biology 25(6): 1163-1179

Davis, A.M., Unmack, P.J., Pusey, B.J., Pearson, R.G. & Morgan, D.L. 2013. Ontogenetic development of intestinal length and relationships to diet in an Australasian fish family (Terapontidae). BMC Evolutionary Biology 13: 53, 16 pp. 

Hammer, M.P. & Walker, K.F. 2004. A catalogue of South Australian freshwater fishes, including new records, range extensions and translocations. Transactions of the Royal Society of South Australia 128(2): 85-97

kerezsy, A., Arthington, A.H. & Balcombe, S.R. 2014. Fish Distribution in Far Western Queensland, Australia: The Importance of Habitat, Connectivity and Natural Flows. Diversity 6(2): 380-395.

Kerezsy, A. & Brooks, S. 2019. Bidyanus welchi. The IUCN Red List of Threatened Species 2019: e.T122906333A123382296. https://dx.doi.org/10.2305/IUCN.UK.2019-3.RLTS.T122906333A123382296.en. Accessed on 11 March 2022.

Hammer, M.P., Adams, M. & Foster, R. 201. Update to the catalogue of South Australian freshwater fishes (Petromyzontida & Actinopterygii). Zootaxa 3593: 59-74.

McCulloch, A.R. & Waite, E.R. 1917. Results of the South Australian Museum expedition to Strzelecki and Coopers Creeks; Pisces. Transactions and Proceedings of the Royal Society of South Australia 41: 472–475 figs 1–2

Merrick, J.R. & Schmida, G.E. 1984. Australian Freshwater Fishes Biology and Management.  Sydney : J.R. Merrick 409 pp. figs 280 col. figs.

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

Scott, T.D., Glover, C.J.M. & Southcott, R.V. 1974. The Marine and Freshwater Fishes of South Australia. Adelaide : Government Printer 392 pp. figs. (as Hephaestus welchi)

Sternberg, D. & Cockayne, B. 2015. Length-length and length-weight relationships of fish species from the Lake Eyre basin, Australia. Journal of Applied Ichthyology 31: 1168-1170.

Unmack, P.J. 2001. Biogeography of Australian freshwater fishes. Journal of Biogeography 28: 1053-1089

Vari, R.P. 1978. The terapon perches (Percoidei, Terapontidae) a cladistic analysis and taxonomic revision. Bulletin of the American Museum of Natural History 159(5): 175–340 figs 1–94. http://hdl.handle.net/2246/1273

Wager, R. & Unmack, P.J. 2000. Fishes of the Lake Eyre catchment of central Australia. Brisbane : Department of Primary Industries Queensland Fisheries Service. 88 pp. 

Quick Facts

CAAB Code:37321010

Conservation:IUCN Least Concern

Habitat:Freshwater rivers, billabongs

Max Size:40 cm SL


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