MOUNT HOLLY, N.C. - A fisherman looking to catch a catfish for dinner instead reeled in a fish that flashed its teeth and bit his knife. Jerry Melton, 46, was fishing in the Catawba River last week when he caught what state wildlife officials later identified as a piranha, a South American carnivorous fish that lives in freshwater.

Jerry Melton holds a piranha July 2, 2007, which he recently caught in the Catawba River, in Mount Holly, N.C.  [AP]

"When I got it on the bank I didn't really know what it was; I hadn't seen anything like it before," Melton said.

When Melton opened the fish's mouth with a pocketknife, he said the fish bit down and left an impression on the blade.

Wildlife officials told Melton on Saturday that he caught a 1 pound, 4 ounce piranha that was probably dumped in the river. Melton was fishing in Mount Holly, a town northwest of Charlotte.

The catch highlights the growing problem of people keeping exotic animals and fish as pets and later dumping them into local waters, said Paul Barrington, an ichthyologist with the Fort Fisher Aquarium. Earlier this year, another fisherman caught a snakehead fish - also a nonnative fish - in Lake Wylie near Charlotte.

"Releasing nonnative fish in our native waters is highly irresponsible because it could have a very adverse affect on the fish in that ecosystem," Barrington said. "Piranha and the snakehead fish have no predators in our waters."

Jacob Rash, a North Carolina Wildlife Resources biologist, said he believes the piranha was the first caught in the Catawba River and possibly the first in the region.

Melton, who is keeping the piranha in his freezer until he can have it mounted, said the experience will keep him out of the river's water.

"I've been fishing there my whole life," he said. "Catching something like that is definitely going to make me think twice about what's in that water."