False Stonefish

Scorpaenopsis diabolus, commonly referred to as the false stonefish, false scorpionfish, or devil scorpionfish, is a species of venomous marine ray-finned fish within the family Scorpaenidae, known as scorpionfishes. This species is equipped with venomous spines and inhabits the tropical regions of the 🇮🇳 Indian and 🌊 Pacific Oceans, including the 🌊 Red Sea. As a benthic predator, it utilizes its exceptional camouflage capabilities to capture unsuspecting prey.

The species was first formally classified as Scorpaena diabolus by the French zoologist Georges Cuvier, inaccurately citing the type locality as "Mer du Croisic," a location in the northern Bay of Biscay. This region is incorrect for the species, which is indigenous to the Indo-West Pacific. The specific epithet, diabolus, translates to "devil," likely referencing the venomous spines located in its dorsal fin. In 1829, Cuvier and Valenciennes noted in "Histoire naturelle des poissons" that inhabitants of the Moluccas Islands in 🇮🇩 Indonesia associate this fish with a "bad omen," sharing accounts of its venom causing fatal injuries and severe suffering.

Scorpaenopsis diabolus features a broad head, expansive mouth, a humped back, and a tapering body, reaching lengths of up to 30 cm (12 in). The dorsal fin is composed of 12 venomous spines and 8 to 10 soft rays, while the anal fin comprises three spines and five to six soft rays. Its rough skin is adorned with low conical projections, spines, and tassels. The coloration is a blend of mottled grey and white with reddish-brown blotches, providing effective camouflage among rocks and corals. The inner pectoral fins display orange, black, and white blotches, which may be "flashed" as a deterrent. This species bears a close resemblance to the reef stonefish (Synanceia verrucosa). Notably, Scorpaenopsis diabolus exhibits biofluorescence; when exposed to blue or ultraviolet light, it fluoresces red, appearing distinct from its appearance under white light. This biofluorescence may enhance both intraspecific communication and camouflage.

This species is found at depths of up to 70 meters (230 feet) throughout the 🇮🇳 Indian and 🌊 Pacific Oceans. Its distribution spans from Southern and Eastern Africa and the 🌊 Red Sea to 🇯🇵 Japan, Hawaii (🇺🇸 United States), 🇵🇫 French Polynesia, 🇦🇺 Australia, and 🇳🇨 New Caledonia (🇫🇷 Overseas France). It often resides on the seabed among rubble, seaweed-coated rocks, or coralline algae-encrusted rocks on reef flats, lagoons, and seaward reef areas.

As a bottom-dwelling fish, Scorpaenopsis diabolus may occasionally be partially obscured by sediment. It acts as an ambush predator feeding on passing invertebrates and small fish. If threatened by a potential predator, it will flare its pectoral fins as a warning. The venomous dorsal spines can cause serious and painful injuries.