Western Smooth Boxfish, Anoplocapros amygdaloides Fraser-Brunner 1941

Other Names: Blue Boxfish, Robust Boxfish

A Western Smooth Boxfish, Anoplocapros amygdaloides, in Eagle Bay, Geographe Bay, Western Australia, April 2006. Source: Erik Schlogl / iNaturalist.org. License: CC BY Attribution-NonCommercial

A pale yellowish boxfish becoming white below, with a brownish tinge above the lower ridge along the side, bone‑white below, and large dark brown to blackish spots on the back and sides. Large males have a pale blue belly and fins.

Cite this page as:
Bray, D.J. 2018, Anoplocapros amygdaloides in Fishes of Australia, accessed 06 May 2021,

Western Smooth Boxfish, Anoplocapros amygdaloides Fraser-Brunner 1941

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Endemic to temperate waters of southern and southwestern Australia, from the eastern part of the Great Australian Bight (South Australia) to Shark Bay (Western Australia). The Western Smooth Boxfish inhabits offshore reefs, seagrass areas and trawl grounds, in depths of 2 to 100 m.


Dorsal fin 10; Anal fin 9-10; Pectoral fin 12; Caudal fin 11.

Dorsal profile straight from snout to dorsal ridge; dorsal and lateral sides with nearly black spots. Two series of bony plates encircling caudal peduncle, anterior ring incomplete laterally, posterior ring continuous, plates covered with rough tubercles.


To 30 cm SL


Body yellowish-white with a brownish tinge above the ventrolateral ridge, bone‑white below; dorsal and lateral sides of body with large, almost black spots; fins clear. Large males with pale blue fins and belly.


Carnivore - feeds on invertebrates.


The sexes are separate and fertilization is external. The eggs and larvae are pelagic.


Of no interest to fisheries, although taken infrequently as incidental bycatch in commercial trawls.


IUCN Red List Status: Least Concern


Although the flesh is not poisonous, a mucous toxin, ostracitoxin, is present in boxfishes and some species can secrete the poison under stress. The toxin kills other fish, and eventually the boxfish themselves if exposed to it. As the precise location of this toxin in all species is not fully understood, boxfish should be considered potentially toxic to humans and their consumption as food should be avoided.

Similar Species

The Western Smooth Boxfish has long been confused with the Eastern Smooth Boxfish, Anoplocapros inermis. A. amygdaloides differs in having a straight the dorsal profile, the caudal peduncle completely encircled by bony plates just in front of caudal fin, and the dorsal and lateral sides with nearly black spots. A. inermis has a convex dorsal profile, the caudal peduncle partially encircled by bony plates just in front of caudal fin, and the dorsal and lateral sides plain, or with yellow to brown spots.

Species Citation

Anoplocapros amygdaloides Fraser‑Brunner, 1941, Ann. Mag. nat. Hist. (11)8: 308, fig. 1B. Type locality: Australia.


Bray, D.J. 2018


Australian Faunal Directory

Western Smooth Boxfish, Anoplocapros amygdaloides Fraser-Brunner 1941


Edgar, G.J. 2008. Australian Marine Life: the plants and animals of temperate waters. Sydney : Reed New Holland 2nd edn, 624 pp. 

Fraser-Brunner, A. 1941. Notes on the plectognath fishes. VII. The Aracanidae, a distinct family of ostraciontoid fishes, with descriptions of two new species. Annals and Magazine of Natural History 11 8(28): 306-313 figs 1-2

Hutchins, J.B. 1990. Fish survey of South Passage, Shark Bay, Western Australia. pp. 263-278 in Berry, P.F., Bradshaw, S.D. & Wilson, B.R. (eds). Research in Shark Bay: Report of the France-Australe Bicentenary Expedition Committee. Perth : Western Australian Museum. (as Anoplocaprus robustus

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 (as Anoplocapros robustus

Hutchins, J.B. 1997. Checklist of fishes of the Houtman Abrolhos Islands, Western Australia. pp. 239-253 in Wells, F. (ed.). The Marine Fauna and Flora of the Houtman Abrolhos Islands, Western Australia. Perth : Western Australian Museum. (as Anoplocapros robustus)

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

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

Kuiter, R.H. 1994. Family Aracanidae. pp. 892-902, figs 788-794 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.

Matsuura, K. 2008. Family Ostraciidae (pp. 842-948). In: Gomon. M.F., Bray, D.J. & Kuiter, R.H (eds). Fishes of Australia's Southern Coast. Sydney : Reed New Holland 928 pp.

May, J.L. & J.G.H. Maxwell. 1986. Trawl fish from temperate waters of Australia. CSIRO Division of Fisheries Research, Tasmania. 492 p.

Quick Facts

CAAB Code:37466015

Danger:Possibly poisonous

Depth:2-100 metres

Habitat:Reef associated

Max Size:30 cm SL


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Species Maps

CAAB distribution map