Roundbelly Cowfish, Lactoria diaphana (Bloch & Schneider 1801)

Other Names: Diaphanous Box-fish, Diaphanous Cowfish, Round-belly Cowfish, Thorny-back Cowfish, Translucent Boxfish, Transparent Boxfish

A Roundbelly Cowfish, Lactoria diaphana, in Moreton Bay, Queensland. Source: Julian K. Finn / Museums Victoria. License: CC by Attribution-NonCommercial

A pale greenish-grey boxfish with a fine honeycomb reticulated pattern and brown blotches. Juveniles are semi-transparent. The carapace of adults has a short spine projecting from above each eye, a broadly rounded lower surface with a posteriorly-directed spine on each side just before the tail base, and a single small spine on the middle of the back.

Cite this page as:
Bray, D.J. 2019, Lactoria diaphana in Fishes of Australia, accessed 14 Jun 2024,

Roundbelly Cowfish, Lactoria diaphana (Bloch & Schneider 1801)

More Info


Northwest Shelf, Western Australia, and the northern Great Barrier Reef, Queensland, to Mallacoota, Victoria, and eastern Tasmania; also at Lord Howe Island and Norfolk Island in the Tasman Sea. Elsewhere, the species occurs in the tropical, Indo-west-central Pacific.
Inhabits coastal and outer reefs, in depths to 50 m. The semi-transparent juveniles are pelagic in hear surface waters.


Dorsal fin 9; Anal fin 9: Pectoral fin 10-11; Caudal fin 10.
Carapace (adults) with a short spine extending from upper edge of each eye; a posteriorly-directed spine on lower rear edge of each side of the carapace just before caudal peduncle, and a single small spine on the middle of the back; dorsal snout profile steep, concave; ventral surface broadly rounded; caudal fin slightly rounded.


Feeds on benthic invertebrates.


Large pelagic juveniles may reach a length of 10 cm, and the species may complete its life cycle in the open sea.


The specific name is from the Latin diaphanus (= transparent).

Species Citation

Ostracion diaphanus Bloch & Schneider 1801, Systema Ichthyologiae: 501. Type locality unknown.


Bray, D.J. 2019


Atlas of Living Australia

Roundbelly Cowfish, Lactoria diaphana (Bloch & Schneider 1801)


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

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

Allen, G.R. & Swainston, R. 1988. The Marine Fishes of North-Western Australia. A field guide for anglers and divers. Perth, WA : Western Australian Museum vi 201 pp., 70 pls.

Bloch, M.E. & Schneider, J.G. 1801. Systema Ichthyologiae Iconibus ex Illustratum. Berlin 584 pp. 110 pls.

Francis, M. 1993. Checklist of the coastal fishes of Lord Howe, Norfolk, and Kermadec Islands, southwest Pacific Ocean. Pacific Science 47(2): 136-170 figs 1-2

Gloerfelt-Tarp, T. & Kailola, P.J. 1984. Trawled Fishes of Southern Indonesia and Northwest Australia. Jakarta : Dir. Gen. Fish. (Indonesia), German Tech. Coop., Aust. Dev. Ass. Bur. 406 pp.

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

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

Johnson, J.W. 1999. Annotated checklist of the fishes of Moreton Bay, Queensland, Australia. Memoirs of the Queensland Museum 43(2):709-762.

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)

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

Kuiter, R.H. 1996. Guide to Sea Fishes of Australia. A comprehensive reference for divers and fishermen. Sydney, NSW, Australia : New Holland Publishers xvii, 434 pp.

Marshall, T.C. 1964. Fishes of the Great Barrier Reef and Coastal Waters of Queensland. Sydney : Angus & Robertson 566 pp. 136 pls.

Matsuura, K. 2001. Ostraciidae, Aracanidae, Triodontidae, Tetraodontidae. pp. 3948-3957 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. 6 pp. 3381-4218.

Moyer, J.T. & Sano, M. 1987. Feeding habits of two sympatric ostraciid fishes at Miyake-jima, Japan. Japanese Journal of Ichthyology 34(1): 108-112.

Randall, J.E. 2005. Reef and shore fishes of the South Pacific. New Caledonia to Tahiti and the Pitcairn Islands. Honolulu : University of Hawaii Press 707 pp.

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.

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.

Russell, B.C. 1983. Annotated checklist of the coral reef fishes in the Capricorn-Bunker group, Great Barrier Reef, Australia. Great Barrier Reef Marine Park Authority. Special Publication Series 1: 1-184 figs 1-2

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.

Quick Facts

CAAB Code:37466007

Depth:1-50 m

Fishing:Aquarium fish

Habitat:Reef associated

Max Size:25 cm TL

Species Image Gallery

Species Maps

CAAB distribution map