What is Swai fish? Why is it unsafe to eat?


Fish is considered as one of the best options for incorporating animal protein as well as omega-3 fatty acids such as EPA and DHA. It also contains good amounts of Vitamin D and Vitamin B2 (riboflavin) and is a great source of minerals like iron, iodine, zinc, magnesium, etc.

The American Heart Association recommends consuming at least two times a week as a part of a healthy diet.

Since traditionally caught, nutritious fish are quite expensive, most people often opt for more affordable varieties such as Swai fish, assuming that all fish are nutritionally equal. However, that is not always the case.

What is Swai fish?

Swai is a type of white-fleshed fish, which is moist, flaky and has a neutral taste. Due to this, it takes on other flavours well and tastes great with sauces and curries.

It is native to the Mekong and Chao Phraya basins in mainland Southeast Asia, especially Vietnam. It was earlier known as Vietnamese catfish, however, in 2003, the United States Congress passed a law that stated that only American catfish belonging to the Ictaluridae family can be labelled as ‘catfish’ and this does not include Swai.

It is known by other names such as panga, cream dory, striped catfish, Vietnamese catfish, tra, basa and even iridescent shark, even though it is neither a shark nor basa. It is quite cheap, costing only about $2 per pound, as opposed to other fish which range from about $9-$20.

Nutritional composition

According to USDA[1], 1 serving (4 ounces) of frozen Swai fillet from Target stores provides approximately:
  • 100 kcal
  • 21 g protein
  • 2 g total fat
  • 30.5 mg Sodium (variable)
  • 25 mg cholesterol
A study conducted in 2014 found that the omega 3 fatty acid (EPA and DHA) content of swai was around 17 mg/100 gm[2]. The sodium content of the fish varies according to the amount of sodium tripolyphosphate (used to retain moisture) added during processing.

Swai fish farming and its concerns

Several environmental organisations such as OceanWise have raised concerns about farming of swai fish because it causes pollution of the ecosystems and also its interference with wild species.

Their major concern is that open cage farming done in the southeast Asian countries results in transfer of diseases to the wild species. The quality of feed used, farming standards and the biological impact of culturing wild species in these farms are also worrisome.

The way swai fish are raised and fed make it unsafe for consumption. Here are the details-

1. Lax inspection

Since swai fish aren’t considered as catfish, they aren’t subject to the same stringent inspection rules as other imported catfish. Large samples have shown to contain vibrio bacteria, which is the major cause of shellfish poisoning, and also E. coli, which, as you know, is responsible for various GI disorders.

2. Filthy water

These fish are mostly farmed in small spaces, which are often filled with waste and sludge. Fish farms produce a lot of waste water, which can’t be legally dumped into rivers. These waters are known to contain various anti-parasitic drugs, pesticides and antibiotics.

3. Antibiotics and other harmful chemicals

Swai fish are mostly factory farmed within small tight ponds. This causes distress and increases their probability of acquiring diseases. These diseased fish are treated with antibiotics, which are then passed on to you when you consume such fish. Also, tests conducted by the Australian Quarantine and Inspection Service found trace levels of malachite green, which is known to cause carcinogenic symptoms.

4. Seafood fraud

Swai fish is available at much cheaper prices than other fish. This leads to mislabelling and then these fish are sold as more expensive fish. Many restaurants, supermarkets and seafood processing plants are involved in such intentional frauds. Sometimes, it may be unintentional. Also, if the fish isn’t identified, such as in dishes like ‘fish and chips’ or ‘fish sandwich’, more often than not, the fish used is swai.

Should you eat it?

In spite of the above claims, the fact remains that swai fish is affordable, tasty and does have a good nutritional profile. If you do want to consume this fish, make sure that you purchase it from a reliable brand and at reliable stores.

You can opt for brands which have eco-certification from independent organisations such as ASC Farmed Pangasius, Naturland Aquaculture Stewardship Council and BAP Certified.

In case you are unable to find such certified brands, it is always better to look for other alternatives, since your health outweighs any other factors.

Better alternatives

If you really love fish, here are some better alternatives than swai:
  1. Sardines-contain high amounts of EPA and DHA, which are responsible for reducing inflammation and maintaining good heart health. They are also excellent sources of Vitamin D, Vitamin B12, selenium and calcium. They have the least impact on the environment and are also quite inexpensive.
  2. Tuna-is rich in potassium, which helps to lower high blood pressure. This, along with a good omega-3 content makes tuna a great anti-inflammatory agent, which positively affects the cardiovascular system. Tuna is also rich in Vitamin C, manganese, selenium and zinc, all of which are great antioxidants known for boosting immunity. Tuna has also been found to be beneficial in reducing the stress levels.
  3. Mackerel-has good amount of protein, omega-3 fatty acids and micronutrients like calcium, phosphorus, potassium, selenium, Vitamin B12 and is one of the least mercury-contaminated fish. It helps to strengthen your bones as well as help in maintaining optimal blood pressure levels.
  4. Salmon-is the most popular fish consumed in America, since it has a rich, creamy texture and buttery flavor. It is very low in saturated fats, but has good protein content. It is also one of the richest sources of Vitamin D and B12. Its major benefit is its abundance of omega-3 fatty acids, which are extremely essential for brain health.
  5. American catfish-these contain high amounts of protein and amino acids. As with other fish, they are also a great source of EPA and DHA, which is beneficial for preventing cardiac diseases. Other nutrients like iodine, zinc, selenium and potassium are also found in these fish.
The stark difference in the omega-3 content of swai fish as compared to salmon can be seen in the graph below-



  • Swai fish is only mediocre when it comes to its nutrient content as compared with other popular fish.
  • It has various controversial issues regarding its farming and distribution.
  • Use of chemicals and antibiotics in the fish farms raises concerns over its health effects.
  • Opting for swai just because of its low cost can prove to be costlier in the long run.

1. fdc.nal.usda.gov/fdc-app.html#/food-details/525008/nutrients
2. ncbi.nlm.nih.gov/pubmed/25108414
About author
Dr Pallavi Pathak
The author, Dr. Pallavi Pathak has a Ph.D in Clinical Nutrition. Her research area includes non communicable diseases, their correlation and risk factors.

Her research on the role of indigenous plants in management of Diabetes Mellitus was well received by her peers. She possesses deep knowledge of nutritional and dietary requirements of patients and has been working as a nutrition consultant almost 2 decades.

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