Although the lionfish (Pterois volitans) is visibly gorgeous, there's much more to this mysterious creature (also referred to as turkeyfish and firefish) than its striking maroon, brown and white stripes, elegant fan-like fins and delicate floating tentacles. When it's not occupying people's saltwater tanks, for example, the popular ornamental yet carnivorous fish has somehow managed to infiltrate tropical waters worldwide, where it has been busy greatly reducing not only native fish populations, but also wreaking havoc on delicate reef ecosystems.
While no one can pinpoint exactly how the alien invasion occurred beyond the species' native Indo-Pacific region, the population explosion is likely to have begun off of the Atlantic Coast in the mid-1980s when an aquarium owner dumped unwanted lionfish into the wild, according to National Geographic. Ocean currents and hurricanes have since aided in the spread from Florida's Atlantic Coast to the Bahamas, throughout the Caribbean Sea and into the Gulf of Mexico. They are mostly found in warm, tropical waters within a variety of habitats, from rocky bottoms to coral and artificial reefs, and can be seen at depths of up to 300 feet (91 meters).
"Lionfish haven been a problem as an invasive species in the Atlantic Ocean since the first sighting in Florida in 1985," says Alex Lawlor, a senior aquarist at the Aquarium of the Pacific in Long Beach, California, in an email interview. "An invasive species is a species that is introduced to a new environment where they have little to no predators and cause harm to the native species. In the case of the lionfish, with no natural predators within the Atlantic Ocean, they eat small fish and crustaceans, often the juveniles of important commercial species, such as snapper."
A lionfish can expand its stomach more than 30 times in volume when eating a large meal, according to Lawlor. It's also capable of long-term fasting, and can go without food for more than 12 weeks without dying. It doesn't help matters that lionfish start reproducing when they are less than 1 year old and can lay up to 30,000 eggs every four days, and have very few natural predators, which means they can erase about 80 percent of a reef fairly quickly. In fact, research has shown that the rapid increase in lionfish coincided with a 65 percent native fish decline in the Atlantic during a two-year period.
Here, some other interesting facts about the lionfish.
1. They Have Venomous Spines Along Their Bodies
The venom glands are located within two grooves on the spines, which would need to pierce the skin to transfer the venom to a person, says Lawlor. "We have not heard of any cases where a lionfish sting has proven to be fatal," she adds. "A sting can cause extreme pain, sweating, respiratory distress and even paralysis that can last for days. The venom is a combination of protein, a neuromuscular toxin and a neurotransmitter called acetylcholine. If you are stung by a lionfish, seek medical attention immediately." According to Medscape, the only known remedy for a lionfish sting is to remove the spines and soak the wound in hot water, no hotter than 114 degrees Fahrenheit (45.6 degrees Celsius), which helps break down the toxin.
2. There Are Ways to Avoid Getting Stung by One
As with many other animals, the best and safest way to enjoy seeing lionfish is to observe them from a distance, says Lawlor. "Keep an eye out for their distinctive coloration when spending time in environments known to be home to lionfish," she cautions. "Be continuously observant of where you put your hands and feet in the water, as lionfish often like to rest along ledges and crevices during the day."
3. They Are Delicious
"People do eat lionfish," says Lawlor, adding that they have a very mild, white meat that can be prepared in several ways, from grilled to blackened. They're even served as sushi. Lionfish are venomous, not poisonous, which means they deliver their toxin through needles, namely their spines. Lionfish have no way to inject venom without their spines, which means that people can safely catch, cook and consume lionfish as long as they avoid the offending spines. "It should be noted that there are areas in the eastern islands of the Caribbean Sea that are considered hot spots for ciguatera fish poisoning [humans acquire this illness by eating reef fish containing naturally occurring toxins, called ciguatoxins], and over 400 different fish species are known to carry ciguatoxin that can cause ciguatera poisoning," she says. "It has been documented through scientific study that lionfish can carry the ciguatera toxin, thus making them potentially unsafe to eat in those specific areas of concern, although there have not been any reported cases of ciguatera poisoning from lionfish."
4. They Like to Ambush Their Predators
"Lionfish primarily feed on small fish and invertebrates," says Lawlor. "They are slow-moving ambush predators, sneaking up on their prey, and use their large mouths to swallow prey whole. Some species have been observed using their pectoral fins to herd prey into an optimal position or 'blowing' water at their prey, so the prey will face them before they strike." As for their natural predators in the Indo-Pacific and Red Sea, she adds, they include sharks, grouper, large eels, frogfish and scorpionfish (to whom they are closely related).
5. They Have Lots of Babies
"Mature lionfish can spawn year-round, and a single female can produce tens of thousands of eggs per spawn," says Lawlor. "The male will become darker in color, and the females will become paler. The males use their spines and fins in a visual display to intimidate their rivals and to attract potential mates. The male and female will circle each other face to face while ascending slowly. Just before reaching the surface, the female will release her eggs and the male will turn upside down to fertilize them."
6. It's Legal to Own a Lionfish as a Pet in the U.S.
"It is legal here in the U.S. to own a lionfish as a pet; however, it is illegal to release a lionfish into the wild," says Lawlor. There are a few different kinds of lionfish available for purchase at most pet stores, with some of the best species for home enthusiasts including the volitans lionfish, russell's lionfish, spot-finned lionfish and dwarf fuzzy lionfish. While most of these fish have the same needs, they are different sizes and will require different tank sizes. Being rather aggressive predators, lionfish should not be put in a tank with any smaller fish, crabs or shrimp because they likely will devour them.