provided by The federal government is a whisker away from declaring what is a catfish, and what isn't. American catfish farmers have demanded that tougher safety rules be imposed on certain fish from Vietnam -- which are hurting their business, the industry says. But U.S. catfish farmers must first get the U.S. Department of Agriculture to say the Vietnamese fish is a catfish. That is a little awkward since just seven years ago the farmers successfully urged Congress to ban the Vietnamese fish from ever being labeled a catfish. In Washington and elsewhere, trade, sometimes as much as science, has a way of defining a species. Something might look, taste and feed off the bottom like a catfish, but until an agency calls it a catfish, it might as well be a duck. American catfish farmers aren't alone in trying to manipulate food names. Three years ago, the Maine lobster industry fought restaurants that offered "langostino lobster," saying that the Chilean crustacean isn't a lobster at all. They called it a crab. The Food and Drug Administration weighed in, approving "langostino lobster" for three species to the consternation of the Maine lobster industry. "Langostinos have scientifically been documented as 'squat lobsters,' " says agency spokeswoman Rita Chappelle, adding that "they are classified as a type of lobster by taxonomists." That includes the book, she adds, "Lobsters of the World" by Dr. Austin Williams. A few years earlier, the European Union tried to rename sardines from Peru and elsewhere as "pilchards" or "sprats." Only a single species harvested in the Mediterranean Sea, the Black Sea and along the European Atlantic coast was a sardine, the EU declared; any slender salty fish from anywhere else was a sardine poseur. The World Trade Organization didn't bite. In 2002, it ruled for Peru. Scientists say there should be no dispute about catfish: The bewhiskered Vietnamese fish, known as pangasius, tra, basa or swai, along with the channel catfish raised primarily in the American South, are two of more than 3,000 catfish species. John Friel, a catfish expert and curator of fishes at Cornell University's Museum of Vertebrates in Ithaca, N.Y., says calling the Vietnamese fish anything but "reeks of absurdity from a scientific point of view." In 2002, when the industry successfully prevented the fish from being labeled a catfish, the measure failed to dent imports, and the U.S. industry sought stiff tariffs a year later. That didn't help much, either. The catfish lobby says its latest campaign to call the Vietnamese fish a catfish isn't a flip-flop from its earlier stance not to designate it as such. "In a scientific sense, pangasius (basa, tra, swai) are in fact Asian catfish, despite labeling and marketing laws" that banned calling them catfish, says Jeff McCord, trade adviser to the Catfish Institute, which promotes U.S.-raised catfish. U.S. catfish farmers say the mild, flaky fish, which turns up at supermarkets as frozen fillets and fish sticks, threatens the $400 million U.S. catfish industry. Pangasius imports totaled $77 million last year, up from $10.7 million in 2000, according to Informa Economics Inc., a Memphis, Tenn., research firm. Joey Lowery, president of trade group Catfish Farmers of America, says U.S. catfish production has shrunk by 25% in recent years, and an adverse USDA decision would "kill our industry." He also says the Vietnamese fish could harm more than U.S. catfish farmers. "There are unsafe products coming into this country," Mr. Lowery says, adding that the Vietnamese use illegal chemicals and unsafe production facilities. Safety was the argument the U.S. industry used in muscling a measure into the 2008 Farm Bill that transferred regulation of all catfish to the USDA, regulator of meat, poultry and eggs, from the FDA, which regulates seafood. The FDA hasn't found that catfish -- foreign or domestic -- poses any greater safety problem than other fish, but it inspects only a small percentage of imports. If the USDA determines the fish isn't a catfish, it could open a boatload of taxonomic troubles if other farmers try similar tactics. In this dogfight, the U.S. industry has a number of adversaries. At Vietnam's embassy in Washington, Thoan V. Ngo, the commercial counselor, says USDA regulation would set up "a de facto trade barrier," adding that Vietnam doesn't allow use of banned chemicals as the U.S. industry asserts. And U.S. importers and processors say the catfish farmers' campaign threatens to cut off their supplies just when some are betting pangasius could be the industry's next big star. At Cornell, Dr. Friel says Washington shouldn't mess with science, and when it comes to taste, "the majority of people probably couldn't tell" the difference.