Don't be surprised if swai fish hasn't hit your radar yet. This freshwater fish, although not common, is actually very versatile, mild in flavor, and inexpensive. Found in Southeast Asia, the swai is a relative of North America's catfish. Like its cousin, swai can grow huge, around 4 feet and close to 100 pounds. Most of the swai found in the United States is farmed in Vietnam and shipped frozen, where it appears on the plate battered and fried, broiled, made into curry, and in a whole range of other tasty dishes.
What is Swai Fish?
Swai (pronounced s-WHY) is in the genus Pangasius, the same group catfish is in. However, in the United States swai cannot be considered catfish—as that designation is saved for members of the family Ictaluridae—even though they taste very similar. Swai does, however, look quite different and doesn't have the large bottom-feeder mouth or whiskers like catfish does.
The bulk of this freshwater fish comes from Vietnam, Thailand, Laos, and Cambodia. Swai gets fished from the rivers in each region along the Mekong Delta. Recent concerns about the vitality of the fish have led to less wild swai on the market and more farmed fish harvested in the aforementioned areas. Since much of this fish is farmed, some batches of swai may have additives or certain chemicals—present in the water—which can make it unsafe to eat if not thoroughly heated.
Compared to other fish, swai is a cheap substitute, often costing a third to quarter the price of other fish. It's comparable to light, white fish such as flounder, sole, and grouper, but because of the similarities, there have been plenty of cases of fish fraud. This mistaken identity has also lead to cooks treating it as a higher quality fish. The best way to be certain swai is on the plate is to source the fish from trusted fishmongers and grocers.
How To Cook Swai Fish
The main thing to keep in mind when cooking swai is that its quality might not be as good as other fish on the market, so it's best to cook it all the way through. Don't eat it raw, rare, or medium-rare, but do prepare it like any other white fish by frying, baking, grilling, or steaming it. It holds up well to being battered and deep-fried and can take the heat of an open flame without falling apart.
The flesh of the swai is a light beige color, which turns creamy white once cooked. Swai also soaks up flavors well, making it a great pairing with rich sauces and marinades, especially citrus-based ones.
What Does Swai Fish Taste Like?
Mild with a hint of sweetness is the best way to describe this light fish. Swai can be more approachable to the palate than its cousin the catfish, and the flesh is tender and flakes well once cooked. It's comparable to catfish in the way it tastes, but overall the swai fish is more delicate both in flavor and texture.
Swai Fish vs. Tilapia
Both swai and tilapia are freshwater fish that cost less than many other types of fish, mainly because they are easily farmed. Swai comes from Southeast Asia and gets shipped frozen to the States, whereas tilapia gets caught and raised all over the world. When cooked, both fish are white and become tender and flaky, making them great options for fried fish cookouts. Tilapia tends to be fattier than swai, and can have darker bits to the flesh. If shopping in North America, one can find fresh tilapia, but swai will always be found frozen. Taste and texture-wise there's not a huge difference, especially when the sauce is the star of the dish.
Swai Fish Recipes
The fish swai most resembles the basic Southern catfish. Use it in any recipe that calls for that ingredient, or in any dish that calls for a flaky, slightly fatty fillet. Swai fish doesn't have a strong flavor and can easily soak up spices or marinades.
Where to Buy Swai Fish
Consumers outside of Southeast Asia are most likely going to encounter swai fish in a frozen state, because it is shipped from that region that way to stay fresh. Rarely will consumers see the fish whole, either; it's mainly sold in fillets for easy use. Most fish counters at normal groceries might not carry swai, but it's often found in Asian markets.
Storing Swai Fish
Keep swai frozen until ready to use. Once defrosted, cook within 24 hours. After the fish gets prepared, it will keep in a sealed container for 3 to 4 days. If there's a pungent, unpleasant fishy smell to the fillet, it's best to discard, since this is one fish that is farmed under less-than-ideal conditions.
Swai fish can be called a lot of names including tra, striped Pangasius, Vietnamese catfish, striped catfish, iridescent shark, sutchi, and basa.
Kulawik, Piotr et al. Microbiological and chemical safety concerns regarding frozen fillets obtained from Pangasius sutchi and Nile tilapia exported to European countries. Journal of the science of food and agriculture vol. 96,4 (2016): 1373-9. doi:10.1002/jsfa.7233