Which fish is widely called the most venomous fish in the world?

The stonefish is widely called the most venomous fish in the world.

Stonefish are scorpaeniform fishes of the Indo-Pacific region, with some related species extending into other warm marine waters. Their name comes from their remarkable resemblance to rocks or fragments of coral. This camouflage helps them ambush prey, but it also makes accidental human contact possible in shallow water.

A stonefish has venomous spines along its dorsal fin. Pressure on the spines can force venom into a wound, and the effects may include intense pain, swelling, and serious systemic symptoms. The venom is defensive rather than a method of actively injecting prey during hunting.

Stonefish are ambush predators that remain motionless until small fish or crustaceans pass close enough to engulf. They are often confused with lionfish because both are venomous members of the scorpionfish group, but lionfish have conspicuous, fan-like fins while stonefish rely heavily on camouflage.