Lionfish are a marine species that are primarily red, brown and white and has a striped, zebra-like appearance. While there are two distinct but visually identical species found in their non-native range, about 97 percent are red lionfish. They grow to about 12-15 inches in length; however they have been noted to be larger in areas where they are not indigenous, exceeding 18 inches. Lionfish can reach maturity in less than a year, but growth slows as they get bigger. Males mature at about 4 inches, females at about 7 inches.
Lionfish have a unique way of spawning. Females release two gelatinous egg masses of about 12,000 to 15,000 eggs each. These masses float and can drift for about 25 days. Lionfish can spawn every four days in warmer climates.
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 which is located on the top of the fish. Two short venomous spines are located on the pelvic fins (one on each side), which is 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, which is 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 a 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. This process allows direct exposure of the wound to the venomous glandular tissue located along the grooved spine. Lionfish fins are not hollow and do not inject venom like a hypodermic needle or the fangs of a snake.
The flesh of the lionfish is not poisonous or venomous. Lionfish also have very bony cheeks, but venom is not located there. Lionfish are stalking predators that often corral prey into a corner. They can consume prey that are more than half of their own length and are known to prey on more than 70 marine fish and invertebrate species including yellowtail snapper, Nassau grouper, parrotfish, banded coral shrimp, and cleaner species. They also compete for food with native predatory fish such as grouper and snapper and may negatively impact the overall reef habitat by eliminating organisms that serve important ecological roles such as herbivorous fish that keep alga in-check. Adult lionfish spread their pectoral fins and use them to “herd” prey. They are the only species known to blow water at prey in an effort to get prey to turn toward the lionfish before being devoured. Lionfish have high fidelity to a location, meaning once they find suitable habitat as an adult they tend to stay there, and can reach densities of more than 200 adults per acre.