It came from the Potomac: even snakeheads have a lobbylist.

• Author: Pfeiffer, Eric
• Position: 10 Miles Square

In Snakehead Terror, a low-budget horror movie broadcast earlier this year on the Sci Fi Channel, the residents of a small Maryland fishing town found themselves plagued by a species of fish accidentally transplanted from China: Channa micropeltes, otherwise known as the snakehead. In the fictional infestation's early stages, the green-skinned fish were merely a nuisance, and local authorities poisoned the town's lake in hopes of eradicating the pesky saw-toothed beast. But the poison did its trick a little too well and killed off most of the lake's other inhabitants along with--or so it seems--the snakeheads. Two years later, a desperate entrepreneur dosed the water with human growth hormone, aiming to revive the local fishing economy. Any 6-year-old with a television set can guess what happened next: It turned out that not all the snakeheads were eradicated, and the survivors returned with appetites matching their newfound dimensions.

Unlike most of what's shown on the Sci Fi Channel, the plot of Snakehead Terror edges uncomfortably close to reality. Two summers ago, the snakehead--a hardy, aggressive species that dates hack to the Paleozoic era and can survive for a time outside of water began to turn up in ponds in Wisconsin and Maryland, devouring plants, other fish, and even small mammals. A few pet owners had acquired the snakeheads as exotic pets and then, apparently had second thoughts. The Washington Post interviewed one such man, Louis Galeano: "Galeano bought four snakeheads from a pet shop in Waldorf [Va.]," the Post reported, "kept them in a 35-gallon tank, and fed them 20 plump goldfish twice a week. They grew like Godzilla, he said, and mealtime became a slaughter. He wouldn't put his hand near the water ... 'They scare me,' he said. 'They just kill and cat and eat and kill.'" After three months, he took the snakeheads to the pet store. Other snakehead owners were less scrupulous and apparently just dumped them into the nearest body of water. Worried about an infestation, local environmental agencies dispatched task forces to places where the fish had turned up. They drained some ponds, poisoned others, and in some cases used electric shocks to stun the fish and bring them up to the surface.

But, as in the movie version, not all the snakeheads were -killed. Last month, an angler fishing for bass in a tributary of the Potomac River, just a few miles south of the monuments on D.C.'s waterfront, caught a 10-pound snakehead that...