Southern Bluespotted Flathead, Platycephalus speculator Klunzinger 1872

Other Names: Bluespot Flathead, Bluespot Flathead, Blue-spot Flathead, Bluespotted Flathead, Castelnaus Flathead, Castelnau's Flathead, Deepwater Flathead, Deep-water Flathead, King Flathead, Lakes Entrance Flathead, Longnose Flathead, Shovelnose Flathead, Southern Dusky Flathead, Southern Flathead, Yank Flathead

A Southern Bluespotted Flathead, Platycephalus speculator, at Point Cook, Port Phillip, Victoria, April 2017. Source: Sascha Schultz / License: CC by Attribution-NonCommercial

A large sandy to dark brown or greyish flathead, becoming paler below, with numerous dark blotches and a few irregularly-shaped blue or white blotches, and 3-5 large black white-edged blotches on the caudal fin that usually do not become progressively smaller towards the top of the fin.  
This is the largest flathead in Victoria's Port Phillip, and is highly prized by both commercial and recreational fishers.

Cite this page as:
Australian National Fish Collection & Bray, D.J. 2020, Platycephalus speculator in Fishes of Australia, accessed 01 Jun 2020,

Southern Bluespotted Flathead, Platycephalus speculator Klunzinger 1872

More Info


Coastal waters of southeastern Australia from Cape Everard (Victoria) to Kalbarri (Western Australia), including around Tasmania. Inhabits sandy areas and weed beds in shallow coastal waters, especially shallow protected bays, to a depth of about 30 m.


Dorsal fin VIII (rarely IX), 14 (rarely 13); Anal fin 14; Caudal fin 15; Pectoral fin 19-21 (rarely 18); Pelvic fin I, 5; Lateral line scales (pored) 80-93.

Body elongate, slightly depressed. Head large (length 28-34% SL), depressed, with several low, mostly spineless ridges; eyes moderately large (16-22% HL) with broad, rounded iris lappet; mouth large with small pointed teeth on jaws, in one or two rows on vomer and in a single row on each palatine, no enlarged canines; two strong preopercular spines at angle of preopercle, lower spine slightly longer than upper; gill rakers on lower limb of first arch long and slender, 3 or 4 on lower limb, 10-12 on upper limb; interopercular flap present.

Scales small, finely ctenoid, covering body and most of head behind eyes; lateral line scales slightly larger than adjacent scales on side, ~95 oblique rows of scales above lateral line, anteriormost scale with small spine or ridge.

First dorsal fin spinous with short base, first spine very short, detached, following spines much longer. Second dorsal fin with moderately long base, anterior rays longest, only slightly shorter than longest first dorsal-fin spine. Anal fin similar in shape, opposite and slightly longer-based than second dorsal fin. Caudal fin truncate to rounded. Pectoral fins moderately small. Pelvic fins long, broad, based below centre of pectoral fins. Swim bladder absent.


Maximum length at least 90 cm TL; maximum weight at least 8 kg.


Sandy to dark brown dorsally with sparsely scattered small blue to white spots often intermingled with dark spots and blotches; no large dark blotch on underside of operculum; pale ventrally. Caudal-fin margin with 3-5 large, round, similar-sized black spots surrounded by white, remainder of fin with dusky brown blotches; pectoral and pelvic fins with faint spots.


Feeds mostly on fishes, and also consumes large benthic crustaceans.


Breeds mostly during the summer and early autumn (December to March). Although spawning typically occurs at sea, some females spawn within estuaries. Larval development has been described in Hyndes, Neira & Potter (1992).


Caught in beach seines, gill nets and haul nets along the southern coast; probably the most commonly marketed flathead in Western Australia.

Species Citation

Platycephalus speculator Klunzinger, 1872, Arch. Naturgesch. 38(1): 28. Type locality: Hobson's Bay, Victoria.


Australian National Fish Collection & Bray, D.J. 2020


Atlas of Living Australia

Southern Bluespotted Flathead, Platycephalus speculator Klunzinger 1872


Coleman, N. 1980. Australian Sea Fishes South of 30ºS. Lane Cove, NSW : Doubleday Australia Pty Ltd 309 pp. (as Platycephalus speculator and P. castelnaui)

Gomon, M.F. 2008. Family Platycephalidae. In: Gomon, M.F., Bray, D.J. & Kuiter, R.H. The Fishes of Australia's Southern Coast. Reed new Holland, Chatswood, Australia.

Grant, E.M. 2002. Guide to Fishes. Redcliffe : EM Grant Pty Ltd 880 pp. 

Hutchins, B. & Swainston, R. 1986. Sea Fishes of Southern Australia. Swainston Publishing, Perth. 179 pp.

Hyndes, G.A., Loneragan, N.R. & Potter, I.C. 1992. Influence of sectioning otoliths on marginal increment trends and age and growth estimates for the flathead Platycephalus speculator. Fishery Bulletin 90: 276-284.

Hyndes, G.A., Neira, F.J. & Potter, I.C. 1992. Reproductive biology and early life history of the marine teleost Platycephalus speculator Klunzinger (Platycephalidae) in a temperate Australian estuary. Journal of Fish Biology 40: 859-874.

Imamura, H. 2006. Rediagnosis of the marbled flathead, Platycephalus marmoratus (Actinopterygii: Teleostei: Platycephalidae), with comments on the composition of the type series. Species Diversity 11: 295-306.

Imamura, H. 2015. Taxonomic revision of the flathead fish genus Platycephalus Bloch, 1785 (Teleostei: Platycephalidae) from Australia, with description of a new species. Zootaxa 3904(2): 151–207 

Klunzinger, C.B. 1872. Zur Fische-fauna von Süd Australien. Archiv für Naturgeschichte 38(1): 17-47 pl. 2

Kuiter, R.H. 1993. Coastal fishes of south-eastern Australia. University of Hawaii Press, Honolulu. 437 p.

Kuiter, R.H. 1994. Family Platycephalidae. pp. 514-523 figs 458-465 in Gomon, M.F., Glover, C.J.M. & Kuiter, R.H. (eds). The Fishes of Australia's South Coast. Adelaide : State Printer 992 pp. 810 figs. 

Macleay, W.J. 1881. Descriptive catalogue of the fishes of Australia. Part 2. Proceedings of the Linnean Society of New South Wales 1 5(4): 510-629 pls 13-14 (as Platycephalus castelnaui)

Prokop, F. 2002. Australian Fish Guide. Croydon South, Victoria : Australian Fishing Network 256 pp. 

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

Whitley, G.P. 1931. New names for Australian fishes. The Australian Zoologist 6(4): 310-334 1 fig. pls 25-27 (as Cacumen speculator)

Whitley, G.P. 1945. New sharks and fishes from Western Australia. Part 2. The Australian Zoologist 11(1): 1-42 figs 1-15 (as Planiprora melsoni)

Whitley, G.P. 1952. Some noteworthy fishes from eastern Australia. Proceedings of the Royal Zoological Society of New South Wales 1950–51: 27-32 figs 1-5 (as Planiprora castelnaui)

Yearsley, G.K., Last, P.R. & Ward, R.D. 2001. Australian Seafood Handbook: an identification guide to domestic species. FRDC / CSIRO Marine Research, 469 pp.

Quick Facts

CAAB Code:37296037

Behaviour:Sandy areas, weed beds

Danger:Venomous spines

Depth:1-30 m

Fishing:Commercial, recreational

Max Size:90 cm; 8 kg


Species Image Gallery

Species Maps

CAAB distribution map