When Virginia biologists identified a fearsome-looking fish snagged in a tributary of the Potomac River as a snakehead, they wrote it off as a castoff from someone’s aquarium.

But when the fish kept turning up, on both the Maryland and Virginia side of the river, they began to fear the worse: The so-called “Frankenfish”—a voracious predator which biologist fear could alter local ecosystems—has found a new home.

Four fish were caught in or near the Potomac from late April to mid-May—two in Virginia and two in Maryland.

All four fish were the same species—northern snakehead—which raised concerns among biologists as some were mature enough to procreate. The first fish was a mature female, while the most recent one caught was a developing male.

After the fourth fish was caught on May 15, Virginia fisheries officials created a snakehead fish panel to assess the possibility that the snakeheads are spawning, said Julia Dixon, spokeswoman for the Virginia Department of Game and Inland Fisheries.

Gary Martel has contacted both Maryland and District of Columbia Fisheries agencies requesting a meeting to coordinate efforts, Dixon said.

“The incident team is working to see what resources are needed to even assess what is needed,” she said. “We’re going to be working closely with Maryland to see if we’re dealing with a population.”

State officials will work with the Smithsonian Institution to see if genetic testing can tell if the Virginia fish is related to one recently found in Maryland.

The snakehead is considered dangerous to the ecosystem because it devours other fish and frogs and has no known predators. Native to Asia and Africa, it’s an anomaly because it can move short distances on land using its fins and live out of water for up to three days.“We learn more and more from these exotics,” Dixon said. “The results are not the desired results.”

While fisheries officials expressed concerns that the snakeheads are spawning, efforts to get rid of them may be futile.

“If they’re in there, there’s nothing anyone's going to be able to do about it,” Virginia fisheries biologist John Odenkirk said last week. He said people may have to accept that the alien fish may likely join a long list of exotic animals that have adapted to the ecosystem. “Maybe 100 years from now, it’ll become part of the ecosystem as common as largemouth bass,” he said.

Officials have gone to great lengths to keep the fish out. In 2000, snakeheads infested a pond in Crofton, MD, spawning hundreds of juveniles. State biologists poisoned and drained the lake.

Largely as a result of the Crofton discovery, at least 20 other states have imposed a ban on the sale, ownership or release of snakeheads.

This first snakehead this year turned up in a pond in Wheaton, MD. That lake was also drained, and biologists were relieved to find no other snakeheads. But the relief was short-lived: Only days later, a snakehead turned up in the Potomac.

If You Catch a Snakehead

Virginia has asked anglers to download a fact sheet about the snakehead from its web site, www.dgif.virginia.gov and to retain any fish they catch that looks like a snakehead and contact the Department of Game and Inland Fisheries at 804-367-1258.

Maryland fisheries officials are posting signs instructing anglers to kill all northern snakeheads, but retain the fish and report them to the DNR at 1-877-620-8367 x8320.