From the beautiful lionfish or lacy scorpionfish to the highly venomous Stonefish this is a family of mostly marine fish that, as the name suggests, are poisonous. Most species are found in the Indopacific living as bottom-dwellers (benthic) feeding on crustaceans and small fish.
With a sedentary lifestyle, resting on sponges or coral, they make excellent photographic subjects. They can be highly cryptic or camouflaged and can even change their colour to match the surrounding environment. Very often cyanobacteria, algae and other parasites can be seen growing on them.
Scorpionfish feed by first opening their mouths and then their gills a fraction of a second apart which creates a lot of suction. Most Scorpionfish, such as the stonefish, wait for prey to pass them by before swallowing, while lionfish often ambush their prey. Lionfish, when not ambushing, may even herd the fish, shrimp, or crab into to a corner before swallowing.
The Reef Stonefish is the most venomous fish in the world. It is not aggressive but can easily be overlooked by a diver. Most incidents, however, are from swimmers who step on them. Its dorsal area is lined with 13 spines that release powerful venom from two sacs attached to each spine. Its venom causes severe pain with possible shock, paralysis, and tissue necrosis depending on the depth of the penetration. A large envenomation can be fatal to humans if not given medical attention within a couple of hours. The pain is said to be so bad that some victims cry out for the affected limb to be amputated! The poisonous sting of Scorpion Fish and Lionfish are said to deliver almost the same level of pain. Stonefish are one of the few gregarious scorpionfishes and are often seen in pairs or even in small groups. If enough food is present, this sedentary animal can stay in the same general area of the reef for months or even years.