Why Are Lionfish So Bad?

If you’ve ever snorkeled or gone scuba diving in the Caribbean or the Gulf of Mexico, you’ve probably met a lionfish. With their dramatic stripes and spiky fins, they look like the rock stars of the reef. But don’t let their gorgeous appearance fool you: lionfish are invasive and voracious predators that do not belong in these waters. Lionfish are bad for the reef because they treat it like an all-you-can-eat buffet. They gobble up native fish and invertebrates, including commercially important species like grouper and snapper. Lionfish are bad for the ocean because their presence disrupts delicate reef ecosystems.

Where Did Lionfish Come From?

How did lionfish get to Florida, North Carolina, the Bahamas, and other parts of the Gulf of Mexico and the Caribbean Sea? Originally from the Indo-Pacific and Red Sea, lionfish have spent the past few decades making themselves at home in the western Atlantic, where they have no natural predators. This lack of natural enemies is one of the main reasons why lionfish are so bad for the reef: they consume native species unchecked.

Did Lionfish Escape From an Aquarium in Florida?

Rumor has long had it that Hurricane Andrew smashed an aquarium near Biscayne Bay in Florida in 1992, releasing a handful of lionfish who then took over the ocean like aquatic Bond villains. However, much as we love a good movie plot, lionfish were already spotted off Florida’s coast as early as 1985. So while lionfish may have escaped from an aquarium in Florida, that is not the source of the lionfish invasion.

Were Lionfish Transported By Ships?

Another popular theory suggests lionfish hitched a ride in the ballast water of ships. Ballast water is the salty soup that ships slurp up for stability, and it’s notorious for spreading invasive aquatic hitchhikers. International regulations now require most ships to treat ballast water before discharge, but not all vessels adhere to these regulations. Despite the hype, studies haven’t found lionfish eggs or larvae in ship ballast water, and their distribution doesn’t match shipping routes. So, it appears that lionfish were not transported to the Caribbean and Gulf of Mexico by ballast water in ships.

So What Caused the Lionfish Invasion?

The likely culprit is much less dramatic: the ornamental aquarium trade. Lionfish became the “it” pet in the 1980s, but many aquarium owners soon realized their new fish was an expensive, spiky eating machine happy to devour all its tank mates. Faced with the choice between endless (and costly) fish shopping or releasing their lionfish into the wild, some owners chose the latter. And so began the lionfish invasion. Florida was once thought to be ground zero, but recent research from the U.S. Geological Survey suggests lionfish may have first been released in the Bahamas or North Carolina—or perhaps all three places at once. No matter where they started, lionfish wasted no time multiplying and spreading across the Atlantic, Caribbean, and Gulf of Mexico.

Why Are Lionfish So Invasive?

Lionfish have no natural predators in the Atlantic. None. Making matters worse, local species fail to recognize them as a threat, making it easy for lionfish to gorge themselves on the native species. To make matters worse, lionfish reproduce at a rate that would make rabbits jealous: females can release up to 50,000 eggs every three days. Their eggs float on ocean currents, helping them colonize new territories faster than you can say “invasive species.”

What Is The Impact of Lionfish On The Environment?

Because lionfish are indiscriminate eaters, they consume herbivores like parrotfish and surgeonfish that normally keep algae in check. The fast-growing algae then competes with coral for space and sunlight, and unchecked algal overgrowth can smother coral reefs. Lionfish can eat fish nearly half their own body length, and some reefs have shown a 79% reduction in baby fish as a result of lionfish predation. The impact of lionfish on the environment is twofold: there are fewer native fish plus stressed coral reefs that are more vulnerable to disease and other environmental threats.

What Are The Efforts to Eradicate Lionfish? Can We Stop the Lionfish Invasion?

Short answer: no. Efforts to eradicate lionfish have little chance of success, but a reduction in their population may be possible through targeted removal efforts. Spearfishing has been the primary approach used to stop the lionfish invasion thus far. Individual spearfishing efforts and organized lionfish derbies—where participants compete to remove the highest number of fish—have helped reduce lionfish numbers in areas accessible to scuba divers. This method mainly targets lionfish living at depths reachable by recreational divers, usually 40 meters or less. However, lionfish have been found as deep as 300 meters, far beyond the reach of most divers. To address this, new solutions are being explored, such as a lionfish trap prototype that is currently being tested for feasibility. The challenge with any fish trap, however, is that they often catch unintended species, posing risks to the environment and potentially entangling other marine life.

What About Feeding Lionfish to Other Fish?

Bad idea. While you technically can feed a speared lionfish to a moray eel, barracuda, or shark, it doesn’t teach them to hunt lionfish on their own. Instead, it teaches them that divers with spears are a reliable source of food. I’ve seen this play out firsthand in the Caribbean. My dive group was out hunting lionfish when a six-foot-long green moray eel suddenly appeared. We didn’t think too much about it at first, as these eels normally just swim on by and don’t pay much attention to divers. But this one was different. He spotted our yellow spears and made a beeline for us. It turns out that divers had been feeding morays in this area their speared lionfish, so the local eels had learned what those spears meant. And this guy was hungry. We hadn’t even caught any lionfish yet, but that didn’t deter him. He kept trying to bite our spears and the “zookeeper” container that is used to hold any caught lionfish. When that didn’t result in a tasty snack, the moray started going after the gear we were wearing, which brought him–and his teeth–dangerously close. Moray eels have razor-sharp teeth that curve backwards, which makes it hard to pull away from a bite. So while it might seem like a good idea to feed lionfish to other fish, it actually creates a risky situation for divers and doesn’t help train predators to control lionfish populations naturally.

Is Lionfish Hunting Working?

Researchers have studied removal programs using volunteer divers with spearguns in several locations, including the Southern Caribbean islands of Bonaire and Curacao, to determine if lionfish hunting is working. These programs have proven effective, with lionfish populations reduced 2.76-fold on Bonaire and 4.14-fold on Curacao in areas accessible to divers. Researchers caution that these areas may be repopulated by lionfish from deeper, unreachable waters or by larvae drifting in from elsewhere. However, if lionfish hunting is an ongoing effort, the resulting lionfish reductions should benefit the reef ecosystem and native fish populations in the hunted areas.

How to Catch Lionfish

Interested in learning a new skill to help protect native fish populations? Learning how to catch lionfish is an adventurous way to help protect the ocean. Across the Caribbean and the Gulf of Mexico, organizations offer training programs for divers who want to learn how to use a pole spear to catch lionfish to join the fight against this invasive species. 

One standout example is the program run by the non-profit organization Roatan Marine Park in Honduras. Here, divers can sign up for a hands-on workshop that covers everything you ever wanted to know about these predators along with the best spearfishing techniques for lionfish.

After completing the training, participants earn a lionfish hunting license and a spear. Armed with knowledge and equipment, newly licensed lionfish hunters are ready to head out and make a tangible impact. Each lionfish removed from the reef helps restore balance to the ecosystem and gives native species a fighting chance.

Can You Eat Lionfish?

Yes, and they’re delicious! Many restaurants serve lionfish tacos and ceviche (but get there early; these dishes tend to sell out). Promoting lionfish as a sustainable seafood option is helping to reduce their numbers. Every lionfish you eat is a win for ocean biodiversity.

How You Can Help Remove Invasive Lionfish

We recommend the program offered by Roatan Marine Park in the West End neighborhood of Roatan in Honduras. We have personally gone through the program and found it to be excellent. Want to combine your lionfish hunting class with another type of educational event? We offer destination continuing medical education (CME) programs with short in-person times in Roatan, Honduras for physicians and other medical providers. Our short in-person format leaves plenty of time to learn how to hunt for lionfish. We hunt lionfish on nearly every dive we do in the waters of Roatan. Come join us!