Venomous fish are species of fish which produce strong mixtures of toxins harmful to humans which they deliberately deliver by means of a bite, sting, or stab, resulting in an envenomation. As a contrast, poisonous fish also produce a strong toxin, but they do not bite, sting, or stab to deliver the toxin, instead being poisonous to eat because the human digestive system does not destroy the toxin they contain in their bodies. Venomous fish do not necessarily cause poisoning if they are eaten, as the digestive system often destroys the venom.
The most venomous known fish is the reef stonefish. It is an ambush predator which waits camouflaged on the bottom.
The beautiful and highly visible lionfish uses venomous barbs around its body as a defence against predators.
The stargazer buries itself out of sight. It can deliver electric shocks as well as venom.
Striped poison fang blenny can deliver a quick and painful bite.
A toxin is a naturally occurring organic poison produced by metabolic activities of living cells or organisms. They occur especially as proteins, often conjugated. The term was first used by organic chemist Ludwig Brieger (1849–1919) and is derived from the word "toxic".
The Amanita muscaria mushroom, an iconic toxic mushroom.