Swai fish is a freshwater fish native to the Southeast Asian countries of Vietnam, Thailand, Laos and Cambodia. Similar to catfish, swai belong to the "Pangasius" family. Though they are food fish, swai are also purchased by hobbyists for their aquariums. In these cases, the fish are commonly referred to as "iridescent sharks."
Swai is a whitefish with a mild, sweet and delicate taste. It is also sold as "shark catfish," "striped catfish" or "tra" and is relatively inexpensive. In the kitchen it is a very versatile fish, because it lends itself equally well to broiling, baking, sautéing and frying. Swai works well as a substitute in recipes featuring any whitefish, including cod, sole and tilapia. A typical 4-ounce serving of plain swai has 21 grams of protein, 1 gram of fat, 110 milligrams of sodium and 80 milligrams of cholesterol.
Most swai in the marketplace are raised on fish farms. Some are also caught wild in rivers, but this population has been seriously depleted due to over-fishing. All swai sold in the United States is farmed.
Swai has raised controversy in the U.S., because some critics say that banned antibiotics are given to the fish in Vietnam. However, in 2014, the Food and Drug Administration expressed no concerned that unapproved drugs were used on swai.