The piscine arsenal: an updated review of venomous fishes

Fishes represent the most diverse group of vertebrates, having inhabited the Earth for approximately 480 million years during which they evolved many specialised adaptations. One such adaptation is the evolution of a venom system, which has convergently arisen on at least 19 separate occasions across their evolutionary history. Venom evolution across fishes has taken two forms: chemical weaponisation of previously evolved defensive spines and the development of an oral venom system. Fish venoms have been shown to contain a myriad of toxin types, some of which may have pharmacological potential. However, due to the labile nature of many toxins, fish venom has not been extensively investigated compared to other venomous groups such as reptiles and arachnids. This review provides an updated scope of our current knowledge regarding the biology, biochemistry, and evolution of fish venom systems. It also attempts to provide a coherent assessment of the dated literature while seeking to address particular issues in order to drive fish venom research further.