The Shenandoah River, pictured here at its confluence with the Potomac in Harpers Ferry, is in the danger of being invaded by the northern snakehead—colloquially known as “the Frankenfish.”
Michael Curi, courtesy of USFWS

An ugly—but tasty—fish could soon invade West Virginia’s waters.

This story was originally published in the April 2018 issue of  Wonderful West Virginia. To subscribe, visit

written by Mikenna Pierotti

It’s a plot straight from Godzilla, King Kong, Alien, and countless other monster movies. A strange creature arrives from parts unknown, terrifying locals with the threat of untold havoc. The difference is, this story is real. 

A creature, colloquially known as “the Frankenfish” for its scaly head and sharp teeth, has invaded waterways from the Potomac River to California, causing a media frenzy and small-scale panic over the past decade. Biologists believe the creatures will soon move into West Virginia.

And while the Frankenfish has turned out to be less harmful than originally predicted—much like the Victorian monster for which it is called—the fish has become a cautionary tale for the myriad ways humans are changing the habitats around us. 

The Making of a Myth

The Frankenfish—whose more common name, the northern snakehead, is no less unfortunate—was first recorded in the United States in a California lake in 1997, according to the U.S. Geological Survey. Others were captured in Florida in 2000 and Illinois in 2004. But the first established population was discovered in 2002 in a manmade pond behind a strip mall in Crofton, Maryland. 

Although no significant populations of northern snakehead exist in West Virginia yet, biologists are almost certain the Asian import will eventually make its way into the state’s waters.
courtesy of USFWS

The fish’s serpentine head, sharp teeth, muscular body, and voracious appetite for everything from fish to birds—as well as tales of the fish breathing above water and traveling across land—spawned dire headlines in newspapers and magazines across the country. The fish also inspired horror movies like Frankenfish, Snakehead Terror, and Swarm of the Snakehead.

Northern snakehead, one of 29 species of the fish, are native to China, Russia, and Korea. But no one is sure how they came to North America. In 2002, The Baltimore Sun blamed a local hobbyist had purchased two of the fish from an exotic animal dealer in New York and released them into the pond when they outgrew his home aquarium. Another story, published in National Geographic in 2016, provides a different origin story. “There was an Asian–American family that lived in the area around the pond in Crofton. And one of the family members became sick,” says Brandon Keplinger, a WVDNR fisheries biologist. When the family member became well again, relatives released the snakehead as a symbolic token of thanks.

However the snakehead appeared, it has made itself at home. By the time Maryland wildlife biologists learned of the fish in Crofton, there were already hundreds of juveniles gobbling up everything in their path. Maryland’s Department of Natural Resources tried removing them, even poisoning them, to no avail. “They began to spread into natural waters. And that was the beginning of the end for the eradication effort,” Keplinger says. 

When the fish were later found in the Potomac River in 2004, it seemed we were on the verge of an environmental catastrophe. Biologists believed West Virginia was next on the Frankenfish’s menu. 

There was good reason to worry. Northern snakehead can reach sexual maturity at just one year old and, with the fish’s ability to mate up to five times a year, a single female can conceivably release as many as 100,000 eggs annually. Many newborn snakehead survive, too, since both parents stick around for weeks after they hatch to guard their young. “They can double their population in a really short period of time if conditions are right,” Keplinger says.

Young snakehead begin life feeding on zooplankton, then moving up to insects and crustaceans and eventually larger fish and animals up to 33 percent their body length, including carp, perch, catfish, and frogs. By the time they reach adulthood, snakehead are able to compete with any other predatory fish, including sport fish like bass.

At maturity, a northern snakehead often exceeds two feet in length. It is an “air sipper,” which means it can live in very low oxygen environments by coming to the surface to breathe. Snakehead also store air in a cavity in their heads and can survive for several days on oxygen trapped there. The fish prefers shallow, stagnant waters like ponds, slow streams, and swamps with lots of vegetation and mud. But it can and does populate canals, reservoirs, lakes, and rivers, and can tolerate freezing temperatures as far north as southern Canada. In its juvenile form, the northern snakehead may even be able to wriggle across land to colonize other waterways.

As Maryland wildlife officials have learned, management is the only option once a population becomes established. Maryland and Virginia have passed laws making it illegal to catch and release snakehead—if you catch one, you have to kill it. Luckily, snakehead are tasty. “They make good tablefare,” says Steve Minkkinen, project leader with the Maryland Fish and Wildlife Conservation Office. “They have white, flaky meat and mild flavor.” 

Anglers are warned to make sure the fish they pull up are actually snakehead and not the native bowfin, an unfortunate lookalike. It’s easy to tell them apart—the snakehead has a telltale flat head and a long fin running along its underbelly, known as an anal fin, while the bowfin has a short fin in the same place as well as a more rounded, fish-like head.

The Real Enemies

So far, no sustained snakehead populations have appeared in West Virginia. That’s probably because they have found better habitats in other areas. “A lot of the locations that they occupy year-round are silty and muddy with lots of vegetation and low-flowing water. Here we have much more steep grades and less aquatic vegetation, because the water systems are being continuously flushed,” Keplinger says. 

Although there are occasional sightings in the state, Keplinger says those are most likely transient fish. “If we do pick something up, it might be looking for new habitat or making long migrational runs. And almost as quickly as they move upstream, they are gone.”

If flathead catfish become established in West Virginia waterways, the fish would likely overtake many native fish populations.
courtesy of USFWS

Minkkinen and Keplinger both agree that, eventually, West Virginia will have its own population of Frankenfish. How quickly that will happen is anyone’s guess. But when it does, fishmageddon is probably not soon to follow. “While demonstrating effects on native species is difficult, we haven’t seen sport fish declining,” reports Minkkinen from Maryland. “The snakehead are just becoming part of the ecosystem here.” 

There are fish that keep Keplinger up at night, however, and they’re not snake-headed monstrosities from across the world. He’s worried about species like the flathead catfish. Native to the nearby Ohio and Mississippi river basins, these fish were intentionally moved into other areas to become sport fish in the 1950s. Today they have invaded the Chesapeake Bay as well as the James, Rappahannock, and Potomac rivers, taking over whole stretches of waterways, preying on native populations like sunfish, and growing to ridiculous size, sometimes 100 pounds or more. In some places, these fish now represent some 75 percent of the fish biomass.

Keplinger fears the general public remains unaware of the consequences of moving aquatic life. “It only takes one or two individuals moving a few flatheads, thinking they want to stock them in a new area because they enjoy fishing for them,” he says. “Well, people had better really enjoy fishing for flatheads, because if they get established, that’s probably all you’ll be pulling up. We have such a popular smallmouth bass and channel catfish sport fishing industry, but all that could change if flatheads start preying on them.”

From above, water appears to be a continuous, single habitat. But that’s an illusion. “Native species are adapted to that particular area for a reason,” Keplinger says. Each part of a waterway has its own unique soils, physical characteristics, and natural and unnatural barriers to movement. These all work together to create many largely self-contained habitats within the same waterway. 

If a new species is introduced, it’s nearly impossible to predict the effects. “It’s like a puzzle. When you take a puzzle piece out and try to fit it into another area in the puzzle, you often have to make alterations to the pieces around it in order to make it fit in that new spot. And you can’t predict how the other pieces will be affected,” Keplinger says. “What pieces will have to bend or break to make it fit together again?” 

That’s why decisions about how to manage species are best left to the experts. 

If you want to help keep your local waterways healthy and full of fish, Keplinger says there are three things you can do. First, never move fish. Always release your fish in the same exact place you found them—unless you happen to catch an invasive snakehead or flathead. In that case, you should take a photo to send to your local DNR fisheries biologist or conservation officer, then cook the fish for dinner.

Second, always use certified disease-free baitfish from your local area. Certified bait fish from a dealer are generally the fry of native species, and therefore won’t harm the local ecosystem if they accidentally escape. Also, make sure the waters you’re fishing in allow the use of bait fish. 

Finally, get out there and fish. “Harvesting fish can actually be an important part of fixing a stunted population,” Keplinger says. “With proper management and knowledge, anglers can benefit the health of the individual fish in that population, allowing them to grow larger and become healthier fish, which can help the entire ecosystem.”