Synanceia is a genus of ray-finned fish belonging to the subfamily Synanceiinae, the stonefish, which is classified within the family Scorpaenidae, the scorpionfish and relatives.

Synanceia was first described as a genus in 1801 by the German naturalists Marcus Elieser Bloch and Johann Gottlob Theaenus Schneider with Scorpaena horrida, which had been described by Carl Linnaeus in 1766 from Ambon Island (Indonesia), as its type species.

The species has potent neurotoxins secreted from glands at the base of their needle-like dorsal fin spines which stick up when disturbed or threatened.

[citation needed] Stonefish have the ability to extend sharp, specialized spines (lachrymal saber) as an additional defense mechanism.

[10][11] The venom of Synanceia consists of a proteinaceous toxin called verrucotoxin (VTX), which modulates Ca2+ channel activity through the β-adrenoceptor-cAMP-PKA pathway.

The Aboriginal people of Northern Australia and the Great Barrier Reef have ways of preparing the fish for eating to avoid poisoning.

[21] There were 25 cases of the use of antivenom for stonefish reported to Commonwealth Serum Laboratories for a one-year period between July 1989 and June 1990, with most from Queensland and four from the Northern Territory.

In 1980 film "Blue Lagoon", Emmeline Lestrange (played by Brooke Shields) unknowingly steps on a stonefish and is almost fatally poisoned.