Uh, Is Swai Fish Healthy? The Top Pros & Cons To Consider

Salmon, tuna, and cod are the fish of choice for many health-conscious eaters. Though delicious and nutritious, these fish can start to feel mundane if you eat them week after week. In search of an exciting alternative, you may have come across swai fish—but what exactly is swai fish, and is it OK to eat?

Firm in texture and mild in flavor, swai is a freshwater fish native to Southeast Asia.

The fish is primarily farmed (rather than wild-caught) in Vietnam, though it's also produced in Thailand, Nepal, Pakistan, India, Bangladesh, Laos, Myanmar, Indonesia, and Cambodia, according to Athena Davis, the North America marketing manager for the Aquaculture Stewardship Council (ASC).

"It's pretty popular in the U.S. as well as some other markets around the world for being a more affordable option for seafood," says Maggie Moon, M.S., R.D., a Los Angeles–based registered dietitian and the author of The MIND Diet. "People may also be seeking it out because it's a lean protein and fish [in general] is good for the heart and the brain."

You may not always see the fish labeled as "swai" in grocery stores or restaurants, though. The fish, which is scientifically known as Pangasianodon hypophthalmus, is also known as pangasius, basa, striped catfish, striped pangasius, and tra, says Corbett Nash, the outreach manager for the Monterey Bay Aquarium Seafood Watch program.

Compared to other white fish, swai is lower in calories and fat; a four-ounce serving of the fish contains 0.5 gram of fat, while tilapia and halibut provide 2 grams and 5 grams, respectively. Swai's protein levels are on par with its counterparts, offering 1 gram less than tilapia and just over 2 grams more than halibut.

Of all the nutrients swai contains, selenium is the standout, says Moon.

A 2013 report by the Institute of Food Research found that a 100-gram serving of pangasius contains 18 micrograms—33% of the recommended intake4—of selenium.

A trace mineral, selenium plays a role in reproduction, thyroid hormone metabolism, and DNA synthesis5. Perhaps most importantly, says Moon, it helps protect the body from oxidative damage and infection.

"Selenium is heavily involved in our antioxidant system in our bodies, so it's very important to our antioxidant defenses and helps lower oxidative stress in the body," says Moon. 

Swai does contain some omega-3 fatty acids, a type of polyunsaturated fatty acid that plays a structural role 7in cell membranes and provides energy for the body—though its levels are lower than other fish like salmon.

"Omega-3s are anti-inflammatory, and they help keep the cell membranes of the neurons in your brain healthy," Moon explains. "The brain is 60% fat, and the omega-3 fats specifically keep it running optimally."

With zero grams of saturated fat and just half a gram of total fat, swai fish is considered a lean protein. And, in turn, the fish can have heart-health benefits when eaten in place of higher-fat proteins, says Moon.

When consumed in excess, saturated fatty acids—found in large amounts in red meat and cheese—increase low-density lipoprotein (LDL or "bad") cholesterol, which raises the risk of cardiovascular disease9.

A standard serving of swai offers roughly 19 milligrams of omega-3 fatty acids, which is on the low end of the 250 to 500 milligrams of combined EPA and DHA (the types found in marine sources) most experts recommend daily, says Moon.

Based on its own environmental sustainability standards, the Monterey Bay Aquarium Seafood Watch program generally recommends pangasius that's certified by the Aquaculture Stewardship Council or Best Aquaculture Practices, says Nash. 

"The ASC's Pangasius Standard includes strict requirements on monitoring water quality and limiting environmental impacts of feed ingredients and waste, among many others," says Davis. "For example, ASC-certified swai farms are required to measure various water parameters (nitrogen, phosphorus, oxygen levels, etc.) on a regular basis and remain within set limits. Treatment systems for waste and sludge need to comply with strict requirements before discharging can occur."

Uncertified swai can come with environmental risks, which is why the Seafood Watch recommends avoiding it. Uncertified swai farms in Vietnam have been linked with large volumes of effluent waste, which could include the fish itself, scales, chemical inputs, or uneaten food, notes Nash.

Another red flag: Data on chemical use (often for controlling parasites and disease) at uncertified swai farms in Vietnam is not available, says Nash.

Overuse of antibiotics in food production can contribute to dangerous antibiotic resistance, and the World Health Organization11 recommends that producers avoid using them on healthy animals.

"Outside of the potential environmental impacts farming can have on local biodiversity if done irresponsibly, farmed fish can affect wild populations if they escape," says Davis. "They can compete with wild fish or breed with them and impact the genetic makeup of wild populations."

A white fish with a mild flavor, barramundi is rich in omega-3s, offering 650 milligrams per serving, says Moon. In a 113-gram serving, barramundi also provides12 more protein (23.1 grams) and fat (roughly 1 gram) than a similar-size serving1 of swai. Plus, the fish generally has a smaller environmental impact than pangasius.

Most catfish in the U.S. is farmed rather than wild-caught, and fish farms in the country are tightly regulated, says Nash. "They do a good job at dealing with the effluent and keeping chemicals under control," he notes. The nutritional profile is pretty similar to swai, as well.

Thanks to its neutral flavor, Alaska pollock can be a suitable alternative to swai, says Moon. The fish provides roughly 250 milligrams of omega-3s per serving, she notes, and it offers more protein (22 grams) than swai14. Plus, the FDA considers15 it a low-mercury option, says Moon.

Wild-caught Alaska pollock is sustainability managed and responsibly harvested under U.S. regulations, according to the National Oceanic and Atmospheric Administration (NOAA).

"There's a significant amount of illegal, unreported, and unregulated seafood that gets laundered into the supply chain," says Max Valentine, Ph.D., the campaign director of Oceana's illegal fishing and transparency campaign in the United States. "Globally, it's estimated that as much as 30% of the marine fish that is caught around the world is either illegally caught or unreported."

What's more, seafood fraud is common. One investigation found that an average of 22% of seafood products were mislabeled—meaning they were not the product being represented to the consumer, says Valentine.

It's important to note that the FDA and NOAA both regulate seafood: The former requires nearly all seafood products to meet certain recordkeeping and traceability standards, and the latter has the Seafood Import Monitoring Program that traces food from the boat to the U.S. border, she explains. The problem: Siluriformes (aka catfish—including swai) are excluded from both of these administrations' mandates, says Valentine.

As a result, "swai and other forms of Siluriformes have been frequently found to be substituted for higher-value fish in numerous seafood fraud studies," says Valentine. "There was a global review a while ago of seafood mislabeling studies, and Siluriformes were found to be the most commonly substituted fish worldwide; they were being sold as a wild-caught or higher-value fish than they actually were."

Before you hand over your credit card or place your order, ask the individual who's selling you the seafood where the fish is from, the species name, and any certifications (such as those from Aquaculture Stewardship Council or Marine Stewardship Council) it has, says Valentine. If you're able to, look directly at the label.

"If the price of something is too good to be true, then it probably is," says Valentine. "If something has a really, really low price per pound that seems uncharacteristic of that product. then there's probably some inherent risk with that product."