Swai fish can contain high levels of antibiotics and chemicals, while other types of fish may provide better nutrients. Swai farming practices also raise environmental concerns.
Swai fish (Pangasius hypophthalmus) is affordable and pleasant to the palate. It’s typically imported from Vietnam. It has a variety of names that include:
- sutchi or sutchi catfish
- Vietnamese catfish
- iridescent shark, though it is not a shark
- panga
- pangasius
- striped catfish
- striped pangasius
- tra
- basa
- cream droy
However, many people who eat swai may not be aware of concerns surrounding its production on crowded fish farms. Seafood Watch, a nonprofit organization run by the Monterey Bay Aquarium, recommends avoiding swai fish.
This article provides the facts about swai fish, helping you decide whether to eat or avoid it.
What is swai, and where does it come from?
Swai is a white-fleshed, moist fish with a firm texture and neutral flavor. It easily takes on the flavor of other ingredients.
It’s native to Asia’s Mekong River. However, swai available to consumers is commonly produced on fish farms in Vietnam. Swai production in the Mekong Delta of Vietnam is one of the largest freshwater fish farming industries worldwide.
Previously, swai imported into the US was called Asian catfish. The US Food and Drug Administration (FDA) passed a law that only fish in the Ictaluridae family, which includes American catfish but not swai, can be labeled or advertised as catfish.
Swai is from a separate but related family called Pangasiidae, and its scientific name is Pangasius hypophthalmus.
Nutritional value of swai
The FDA encourages eating fish as it supplies essential nutrients, such as lean protein and heart-healthy omega-3 fat.
Swai’s protein content is average compared to other common fish.
However, according to 2014 research, it offers very little fatty acid content (17 mg per 100 grams) compared to other popular fish, including Chilean sea bass (2430 mg per 100 grams) and salmon (717 to 1533 mg per 100 grams).
A 4-ounce (112-gram) serving of uncooked swai contains:
- Calories: 79
- Protein: 19 grams
- Fat: .5 grams
- Cholesterol: 50 grams
- Carbs: 0 grams
- Calcium: 13.4 mg
- Sodium: 30.2 mg
The sodium in swai may be higher or lower than shown above based on how much sodium tripolyphosphate, an additive to retain moisture, is used during processing.
Swai may be a good source of selenium, niacin, and vitamin B12. However, the amounts can vary depending on what the fish is fed.
Swai raised in farms don’t have particularly healthy diets. They’re typically fed rice bran, soy, canola, and fish by-products. The soy and canola products are commonly genetically modified.
Concerns about swai fish farming
The Monterey Bay Aquarium’s Seafood Watch program recommends avoiding swai, as some swai fish farms generate waste products illegally dumped into rivers. They also note that swai farms can have a negative effect on local habitats and that the farms may spread pathogens and parasites to wild animals in those habitats.
The improper disposal of wastewater is especially concerning because swai fish farms use many chemical agents, including:
- disinfectants
- anti-parasitic drugs
- antibiotics
The European Parliament has also raised safety concerns relating to swai fish and noted that several retail chains in Europe and Italy have banned it.
Mercury contamination is another consideration. According to 2018 research, the mercury content in swai from Vietnam varied by sample between acceptable and slightly above acceptable levels.
These challenges suggest the need for better water quality on swai fish farms and better quality control checks of the fish during the import process.
Antibiotics are heavily used during production
When swai and other fish are grown on crowded fish farms, the risk of infectious diseases in the fish increases.
In one 2016 study, 70 to 80% of swai samples exported to Poland, Germany, and Ukraine contained Vibrio bacteria, a microbe commonly involved in shellfish food poisoning in people.
To prevent bacterial infections, swai are often regularly given antibiotics and other drugs. However, there are drawbacks. Residues of antibiotics may remain in the fish, and the drugs can get into nearby waterways. These substances are also banned in some European countries.
In an older study of imported seafood, swai and other Asian seafood most frequently exceeded drug residue limits. Vietnam had the greatest number of drug residue violations among countries that export fish.
Additionally, even if fish is properly inspected and antibiotics and other drug residues are below legal limits, their frequent use can promote bacteria resistance to the drugs.
You may be eating swai unknowingly
In a study by Oceana, an international ocean conservation and advocacy organization, swai was one of the three types of fish most commonly substituted for more expensive fish. The organization found swai was sold as 18 different types of fish, most commonly mislabeled as perch, grouper, or sole.
Such mislabeling may happen at restaurants, supermarkets, and seafood processing plants. Sometimes, this mislabeling is deliberate fraud since swai is inexpensive, and other times, it’s unintentional.
Seafood often travels a long way from where it’s caught to where you buy it, making it more difficult to trace its origin. For example, there’s no easy way for restaurant owners to check that a box of fish they purchased is what it says it is.
Moreover, if a type of fish isn’t identified, such as if you’re ordering a fish sandwich at a restaurant that doesn’t specify the type of fish, it could be swai.
In a 2016 study of fish products served at 37 restaurants in a southeastern US city, about 67% of dishes listed as “fish” on the menu were swai.
Alternatives to swai
If you like swai, buy brands that have eco-certification from an independent group, such as the Aquaculture Stewardship Council. Such brands typically include the certifying agency’s logo on the package.
Certification indicates efforts to reduce pollutants that can contribute to climate change and harm water quality.
Additionally, don’t eat raw or undercooked swai. Cook fish to an internal temperature of 145℉ (62.8℃) to destroy potentially harmful bacteria, such as Vibrio.
If you choose to pass on swai, there are plenty of good alternatives. For white-fleshed fish, consider:
- wild-caught US catfish
- Pacific cod (from the United States and Canada)
- haddock
- sole
- flounder
For fish packed with omega-3s, some of your best options that don’t contain excess mercury are:
- wild-caught salmon
- sardines
- herring
- anchovies
- Pacific oysters
- freshwater trout
It’s best to eat various kinds of fish rather than the same type all the time. This helps reduce possible risks from over-exposure to potentially harmful contaminants in one kind of fish.
The bottom line
Swai fish has a mediocre nutritional profile and may best be avoided.
It’s imported from densely packed fish farms, where chemicals and antibiotics are used in excess, causing water pollution and health concerns.
It’s sometimes mislabeled and sold as higher-value fish. If you decide to eat it, consider choosing a brand bearing an eco-certificate.
Generally, it’s best to eat a variety of types of fish. Healthy alternatives to swai include haddock, sole, salmon, and many others.