Estuarine Stonefish, Synanceia horrida (Linnaeus 1766)

Other Names: Hollow-cheek Stonefish, Horrid Stonefish, Rough Stonefish, True Stonefish

An Estuarine Stonefish, Synanceia horrida, at Karimun, Kepulauan Riau, Indonesia. Source: Ria Tan / Flickr EOL Images. License: CC by Attribution-NonCommercial-ShareAlike


A drab brownish-grey to reddish or greenish-brown stonefish with large fleshy pectoral fins and warty, scaleless skin often covered in filamentous algae. The relatively small eyes are strongly elevated on the head, with a deep pit behind the eyes and a deep pit below each eye. 

These superbly camouflaged ambush predators are extremely difficult to see. The robust dorsal-fin spines are grooved with a venom gland at their base, each spine surrounded by a fleshy sheath of skin. Along with the Reef Stonefish, they are considered to be the most venomous of fishes, and a sting can be agonizing and even fatal. While no deaths have been recorded in Australia since the arrival of Europeans, an antivenom, developed in 1959, reduces the likelihood of death.

Video of an Estuarine Stonefish

Video of a small Estuarine Stonefish feeding at the surface on unsuspecting prey near Cairns Marina, April 2016. 

Meet the stonefish, the world's most venomous fish.

Cite this page as:
Bray, D.J. 2022, Synanceia horrida in Fishes of Australia, accessed 16 Apr 2024,

Estuarine Stonefish, Synanceia horrida (Linnaeus 1766)

More Info


Shark Bay, Western Australia, around the tropical north to Coffs Harbour, New South Wales. Elsewhere the species occurs in the Indo-west Pacific: India to Australia, and north to the Philippines and southern China and Japan. 
Inhabits sandy and muddy areas on sheltered coastal reefs and estuaries, often in very shallow water amongst coral rubble and rocks on reef flats, and in seagrass beds. Estuarine Stonefish are solitary and usually lie motionless and partly buried during the day.


Dorsal fin XIII-XIV, 6; Anal fin III, 5; Pectoral fin 15-17.

Head broad, depressed; eyes small, widely separated, well-elevated on the head and directed upward; a deep pit behind and below each eye; mouth large, opening dorsally with a vertical gape; lips fringed with cirri. 

Dorsal-fin spines subequal in length, second to fourth spines longest; pectoral fins large, fleshy.

Skin warty, scaleless, often with filamentous algae; 13-14 sharp strong dorsal-fin spines, second to fourth the longest, each in a thick sheath of skin with a venom gland at base; pectoral fins large, fleshy.


A nocturnal ambush predator that feeds on small fishes, crustaceans and cephalopod molluscs.


Stonefish are considered to be the most venomous of fishes. Each stout dorsal-fin spine has a groove linked to two venom glands at its base. Rather than fleeing when disturbed, the stonefish usually remains very still, perhaps erecting the dorsal fin for protection. When an unwary victim accidentally steps on the fish, the spines act like hypodermic syringes, forcing venom into puncture wounds.  

The venom affects the cardiovascular and neuromuscular systems. The sting is excruciatingly painful and may even prove fatal unless the victim is administered antivenom. Although no deaths from stonefish stings have been recorded in Australia since the arrival of Europeans, deaths have been reported from elsewhere in the Indo-Pacific.

Estuarine Stonefish use their large fleshy pectoral fins to create a shallow depression in sandy or rubble bottoms. They scoop out the sand and pile it around their sides, and then lie motionless, undetected except by the keenest observer.

Similar Species

The Reef Stonefish, Synanceia verrucosa, differs in having the eyes only slightly elevated on the head, with a deep pit behind the eyes and a smaller pit below each eye.


The specific name is from the Latin horridus (= dreadful, horrid, frightful) presumably in reference to the appearance of this species.

Species Citation

Scorpaena horrida Linnaeus, 1766, Systema Naturae 1: 453. Type locality: East Indies [Ambon Island, Molucca Islands, Indonesia].


Bray, D.J. 2022


Atlas of Living Australia

Estuarine Stonefish, Synanceia horrida (Linnaeus 1766)


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.

Blaber, S.J.M., Young, J.W. & Dunning, M.C. 1985. Community structure and zoogeographic affinities of the coastal fishes of the Dampier region of north-western Australia. Australian Journal of Marine and Freshwater Research 36: 247-266,

Chen, D., Kini, R.M., Yuen, R. & Khoo, H.E. 1997. Haemolytic activity of stonustoxin from stonefish (Synanceja horrida) venom: pore formation and the role of cationic amino acid residues. Biochem Journal 325(3): 685-691.

Coleman, N. 1981. Australian Sea Fishes North of 30°S. Lane Cove, NSW : Doubleday Australia Pty Ltd 297 pp.

Eschmeyer, W.N. & Rama-Rao, K.V. 1973. Two new stonefishes (Pisces : Scorpaenidae) from the Indo-west Pacific, with a synopsis of the subfamily Synanceiinae. Proceedings of the California Academy of Sciences 39(18): 337-382 figs 1-13 

Günther, A. 1860. Catalogue of the Fishes in the British Museum. Catalogue of the acanthopterygian fishes in the collection of the British Museum. Squamipinnes, Cirrhitidae, Triglidae, Trachinidae, Sciaenidae, Polynemidae, Sphyraenidae, Trichiuridae, Scombridae, Carangidae, Xiphiidae. London : British Museum Vol. 2 548 pp.

Halstead, B.W., Auerbach, P.S. & Campbell, D.R. 1990. A colour atlas of dangerous marine animals. Wolfe Medical Publications Ltd, W.S. Cowell Ltd, Ipswich, England. 192 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)

Larson, H.K. & Williams, R.S. 1997. Darwin Harbour fishes: a survey and annotated checklist. pp. 339-380 in Hanley, H.R., Caswell, G., Megirian, D. & Larson, H.K. (eds). The Marine Flora and Fauna of Darwin Harbour, Northern Territory, Australia. Proceedings of the Sixth International Marine Biology Workshop. Darwin : Museum and Art Gallery of the Northern Territory 466 pp.

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

Linnaeus, C. 1766. Systema Naturae per Regna Tria Naturae, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Editio duodecima, reformata. Holmiae : Laurentii Salvii Vol. 1 1327 & 36 pp.

Motomura, H., Matsuura, K. & Khan, M. 2018. Synanceia horrida. The IUCN Red List of Threatened Species 2018: e.T114179968A116344072. Downloaded on 19 February 2020.

Poss, S.G. 1999. Families Scorpaenidae, Caracanthidae, Aploactinidae. pp. 2291-2358 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. 4 2069-2790 pp.

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.

Richardson, J. 1842. Contributions to the ichthyology of Australia. Annals and Magazine of Natural History ns 9(59): 384-393 (described as Synanceia trachynis) See ref at BHL

Smith, W.L., Everman, E. & Richardson, C. 2018. Phylogeny and taxonomy of flatheads, scorpionfishes, sea robins, and stonefishes (Percomorpha: Scorpaeniformes) and the evolution of the lachrymal saber. Copeia 106(1): 94–119.

Smith, W.L. & Wheeler, W.C. 2006. Venom evolution widespread in fishes: a phylogenetic rode map for the bioprospecting of piscine venoms. Journal of Heredity 97(3): 206-217.

Ziegman, R., Undheim, E., Baillie, G., Jones, A. & Alewood, P. 2019. Investigation of the estuarine stonefish (Synanceia horrida) venom composition. Journal of Proteomics 201: 12-26.

Quick Facts

CAAB Code:37287049

Conservation:IUCN Least Concern

Danger:Extremely venomous spines

Depth:0-40 m

Habitat:Reef associated

Max Size:60 cm TL

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Species Maps

CAAB distribution map