The venomous fish known for camouflaging itself as a rock and delivering extremely painful stings is the stonefish. Stonefish belong mainly to the genus Synanceia and live in shallow tropical waters of the Indo-Pacific, where their mottled, warty bodies blend into reefs, rocks, and seabeds.
Rather than actively attacking people, a stonefish usually relies on camouflage and remains motionless as an ambush predator. When stepped on or pressed, it raises sharp dorsal spines. Glands at the bases of those spines release venom under pressure, making an accidental foot injury the most common type of encounter.
The reef stonefish, Synanceia verrucosa, is often described as the most venomous known fish. Its venom can produce immediate, intense pain as well as swelling, paralysis, cardiovascular problems, and tissue damage. Severe cases may be fatal. Hot-water treatment and species-specific antivenom are important medical measures, while lionfish and pufferfish are different animals with different defenses.