Lionfish have 18 venomous spines that are used defensively against predators. These spines should be avoided during capture and handling because of their ability to cause painful injuries.
Thirteen long venomous spines are located along the front of the dorsal fin, located on the top of the fish. Two short venomous spines are located on the pelvic fins (one on each side), located on the bottom of the fish closest to the fish’s head. Three additional venomous spines are located along the front edge of the anal fin, located on the bottom of the fish nearest the tail. The large and featherlike pectoral fins and the tail fin do not contain venomous spines. Each bony and venomous spine is grooved and covered with skin-like tissue. During a sting, the skin-like covering is torn and retracted as the spine is inserted into the body of a predator.