Estuarine Stonefish, Synanceia horrida (Linnaeus 1766)

Other Names: 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 warty, scaleless skin, fleshy pectoral fins, a deep pit behind and below each eye, and eyes that are strongly elevated on the head. 

Estuarine Stonefish are superbly camouflaged to match their surroundings and are extremely difficult to see. The robust dorsal-fin spines are grooved and have a venom gland at the base. 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:
Dianne J. Bray, Synanceia horrida in Fishes of Australia, accessed 15 Jul 2020,

Estuarine Stonefish, Synanceia horrida (Linnaeus 1766)

More Info


Recorded in Australia from Shark Bay, Western Australia, to Coffs Harbour, New South Wales. Found elsewhere in the Indo-west Pacific. Estuarine Stonefish inhabit sheltered coastal reefs and estuaries, often in very shallow water amongst coral rubble and rocks on reef flats, and in seagrass beds. They are solitary and usually lie motionless and partly buried in sand during the day.


Meristic features: Dorsal fin XIII-XIV (usually XIII), 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. Warty, scaleless skin, 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.


Nocturnal carnivore - 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.

Species Citation

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


Dianne J. Bray

Estuarine Stonefish, Synanceia horrida (Linnaeus 1766)


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Quick Facts

CAAB Code:37287049

Danger:Extremely venomous spines

Depth:0-40 m

Habitat:Reef associated

Max Size:60 cm TL

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