Blowhole Perch, Caesioscorpis theagenes Whitley 1945

Other Names: Fusilier Sweep, Green Fusilier, Southern Fusilier

Blowhole Perch, Caesioscorpis theagenes, at Fremantle, Western Australia, April 2019. Source: jmartincrossley / License: CC By Attribution-NonCommercial

A relatively slender silvery schooling fish with a silvery greenish-yellow back, dorsal and caudal fins, a pointed snout, protrusible jaws, a forked tail, and scales covering much of the soft dorsal and anal fins.

Cite this page as:
Bray, D.J. 2020, Caesioscorpis theagenes in Fishes of Australia, accessed 23 Sep 2020,

Blowhole Perch, Caesioscorpis theagenes Whitley 1945

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Endemic to Western Australia, from Albany to Shark Bay. Forms small to large schools on offshore reefs along the west coast.


Description from Whitley (1945): Dorsal XI, 21; Anal fin III, 18; Pectoral fin ii, 14; Pelvic fin I, 5; Caudal fin 16; Lateral line 49 to hypural + 5 on tail. 

Head acutely pointed, compressed, tapering ventrally, scaly except for tip of snout and chin. Eyes large, lateral. Interorbital convex, scaly. Pre-orbital entire. Maxillary thin, truncate. Lower jaw terminal, mandibular rami elevated and extensive. Small teeth in jaws, apparently none on palate. Nostrils rounded. No barbels. Operculum with two small flat spines. Preoperculum thin, venulose, crenulated at edge. Gill-membranes united by small membrane across narrow isthmus. Body lenticular, compressed. 
Scales of moderate size, ciliated, imbricate, adherent, thin. Lateral line complete, tubes straight. Vent little before anal fin, no papilla. 
Dorsal fin with eleven heteracanth spines, anal with three. Spines and rays compactly united by membranes. Soft dorsal and anal fins with plus or minus twenty rays, covered by scales. Fins not falcate or with produced lobes. Pectorals shorter than head with lower rays branched. Pelvics behind level of pectoral base. Caudal forked. 


Mostly silvery light green above and silvery below.

Species Citation

Caesioscorpis theagenes Whitley 1945, Aust. Zool. 11(1): 21, fig. 11. Type locality: Blowholes, north of Carnarvon, Western Australian.


Bray, D.J. 2020


Atlas of Living Australia

Blowhole Perch, Caesioscorpis theagenes Whitley 1945


Hoschke, A., Whisson, G. & Moore, G.I. 2019. Complete list of fishes from Rottnest Island. pp. 150-161 in Whisson, G. & Hoschke, A. (eds.) The Rottnest Island fish book. 2nd ed. Perth: Aqua Research and Monitoring Services.

Hutchins, J.B. 1994. A survey of the nearshore reef fish fauna of Western Australia's west and south coasts — The Leeuwin Province. Records of the Western Australian Museum, Supplement 46: 1-66 figs 1-6 

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

Hutchins, J.B. & Thompson, M. 1983. The Marine and Estuarine Fishes of South-western Australia. Perth : Western Australian Museum 103 pp. 345 figs.

Whitley, G.P. 1945. New sharks and fishes from Western Australia. Part 2. The Australian Zoologist 11(1): 1-42 figs 1-15 See ref at BHL

Quick Facts

CAAB Code:37311135

Depth:0-30 m

Habitat:Reef associated

Max Size:18 cm TL


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