Updated

A slippery, black, eel-like fish with a hearty appetite for other fish, birds and frogs is getting its comeuppance in the United States as government officials crack down on the dreaded snakehead, banning 28 species from importation.

"Snakeheads are like something from a bad horror movie. These fish are top-level predators that will eat virtually anything in their path," Interior Secretary Gale Norton said Tuesday.

"They have the potential to cause enormous damage to our valuable recreational and commercial fisheries. We must do everything we can to prevent them from entering our waters, either accidentally or intentionally," she said.

The freshwater "Frankenfish" — as they are not so affectionately called — hail from Asia and are brought to the United States for aquariums and as a delicacy mainly eaten by residents of Asian descent.

But the snakeheads are not as harmless as other aquarium dwellers. For one, they can walk across land to find new sources of food, living out of the water for up to three days.

Fishmongers in Asia like the fish for its staying power since they can always be sold fresh in shops. But Norton said Tuesday that even Asian sources have reported attacks on people by the fish.

And in the United States, the snakeheads have created another headache, a feeding frenzy on indigenous and some endangered fish.

"Very aggressive feeder; if it thinks it can fit something in its mouth, it will likely try to do so," said Michael Flattery of the U.S. Fish and Wildlife Service.

Snakeheads have been found reproducing in the waters of Maryland, California and Florida. Residents in Maine, Massachusetts, Rhode Island, and Hawaii have caught individual snakeheads.

Investigators in Maryland say their problem arose when a man ordered two snakeheads from an Asian market that he planned to use to make soup for his ailing sister. By the time he received the fish, the sister had recovered, so he kept them in a tank until they became too large, at which time the man decided to release them into a nearby pond.

"They became unwanted pets to the individual and they felt the need to dispose of them," said Maryland Department of Natural Resources Police Captain Mark Saunders.

The released snakeheads happened to be a male and a female and they have produced many babies — possibly thousands of them.

With their huge appetites and mobility, specialists are looking for ways to prevent the snakeheads from threatening other fish.

That will start at the border with U.S. Fish and Wildlife Service and U.S. Customs inspectors seizing any live snakeheads and their eggs. Penalties for those caught transporting snakeheads are up to six months in prison, with $5,000 fines for individuals and $10,000 fines for organizations. Scientific, educational and zoological groups may be granted exceptions.

In the states, Maryland is taking the lead on curbing its population, considering whether to poison the snakeheads. However, the poison would also kill all the other fish in the pond.

Even so, it's difficult to find opposition to the crackdown on the snakeheads since officials say it could wipe out more than 100 endangered fish.