Swai Fish

Swai fish, also known as iridescent sharks, is a type of shark catfish native to Vietnam.

These omnivorous bottom feeders live in the Mekong river and migrate upstream when the water levels rise in the late summer.

When left to their own devices, iridescent sharks can get as big as 100 pounds. Commercial farmers frequently breed large quantities of swai to sell as a popular replacement for catfish meat. You can also find small iridescent sharks that have been stunted in growth to serve as aquarium pets.

3 Incredible Swai Fish Facts!

• Glowing fins: The iridescent shark’s name comes from the edges of its fins, which have a shimmery glow that is visible even in the dark.
• Endless appetite: Swai are known for eating nearly any kind of food they come across. Plants, crustaceans, and smaller fish are no match for the iridescent shark’s omnivorous appetite.
• Sharkfin style: Swai is a type of pangasius or shark catfish. Although they’re not actually sharks, these catfish all feature a dorsal fin and a silvery, shark-like appearance.

Classification and Scientific Name

The scientific name for swai fish is Pangasianodon hypophthalmus. In Vietnam, they are often referred to as tra fish; they may also be mistaken for the related basa, or Pangasius bocourti. When they’re not being sold as livestock, these silver creatures are frequently called iridescent sharks for their glowing fins and shark-like appearance.

Iridescent sharks belong to the Actinopterygii class and Pangasiidae family of shark catfish. They are related to American catfish, but they are distinguished by their shark-like dorsal fins. In reference to their scientific name, shark catfish are also frequently called pangasius by members of the research community.

Evolution and Origins

Swai is originally from the Mekong River in Asia, but most of the swai that people can buy comes from fish farms in Vietnam. Actually, Vietnam has one of the biggest industries for farming swai in the world, located in the Mekong Delta.

Swai fish and other fish imported from Vietnam are frequently regarded as “unclean” and generate a number of health issues due to their uneven quality. The majority of the swai fish (Basa) brought into the United States is native to Vietnam.

Furthermore, It may be recommended to stay away from Swai fish because of its subpar nutritional profile. It is imported from tightly populated fish farms where excessive amounts of pesticides and antibiotics are utilized, polluting the environment and endangering human health. Sometimes it is marketed under false pretenses as more expensive fish.

Different Types

Several names can be used to refer to swai fish, such as tra, striped Pangasius, Vietnamese catfish, striped catfish, iridescent shark, sutchi, and basa. There are only one sole species of this kind.

Appearance

Iridescent sharks are Asian catfish with silver scales, beige skin, and small whiskers. Like other shark catfish, pangasius has a small dorsal fin on the top of their bodies. The edges of a pangasius’ fins glow faintly underwater, making them a popular choice for aquariums.

Young iridescent sharks can grow to be anywhere from 1 to 4 feet long and typically weigh between 50 to 100 pounds. The largest ever recorded swai fish weigh 44 kilograms or about 97 pounds.

The growth of pangasius can be stunted by diet or a confined space, which is why iridescent sharks that live in aquariums are usually so much smaller than their wild or commercially-grown counterparts.

Distribution, Population, and Habitat

Iridescent sharks are native to Asia and are most commonly found within the country of Vietnam. Most wild pangasius lives in the Mekong river, where they swim upstream from the Maeklong basin. Some pangasius also swims downstream into the Chao Phraya.

Pangasius are freshwater fish and are popularly farmed in ponds, rice paddies, and similar structures. Nearly all commercially sold iridescent sharks are bred as livestock; you shouldn’t expect to purchase wild pangasius at a normal market.

Although population numbers are not available, iridescent sharks are considered to be endangered in their natural habitats.

Predators and Prey

Iridescent sharks are omnivorous animals that feed on crustaceans, algae, bugs, and other small fish. A swai will eat nearly anything it can catch as it grows to its full size of 100 pounds. When they are farmed commercially, pangasius is typically fed a diet that consists of barley, oats, and other types of grain.

Pangasius has no natural means of self-defense, making them a popular target for all predatory animals in their native region, including birds, mammals, and other large fish. Human fishermen are one of the primary threats to iridescent sharks, and overfishing is likely responsible for their current status of endangered.

Reproduction and Lifespan

Iridescent sharks are egg-laying creatures that live in large clusters. Like other types of catfish, pangasius breed in a migratory pattern that involves swimming upstream to a breeding ground during the late summer months.

Due to their wild nature, iridescent sharks are particularly difficult to breed in captivity. Pangasius farmers tend to keep the fish in large ponds with many other members of the same species to ensure adequate breeding conditions. Due to the lack of research on this particular type of fish, it is unknown how long a swai might live in the wild. In captivity, a well-loved iridescent shark might manage to have a lifespan as long as twenty years.

Fishing and Cooking

Although iridescent sharks are found naturally in the rivers of Vietnam, most commercial swai production takes place in controlled farming environments. Large groups of pangasius are kept in ponds, rice fields, and other watery areas until they are big enough to harvest for consumption.

In cooking, swai meat is used as a popular replacement for American catfish. The taste is described as sweet and significantly milder than their catfish cousins. Swai is known to have a tougher texture and slightly blander taste than basa, another shark catfish that is found in the same region.

Swai meat is a good source of nutrition with plenty of protein and vitamin B12. Unless you live in Vietnam, you are most likely to find pangasius meat in the frozen section, where it can stay fresh and delicious for up to a year at a time. Frozen pangasius meat can be baked, broiled, or fried to achieve the best taste. Just remember to thaw your frozen fish out before you cook it to prevent too much moisture from entering the dish.

1. VASEP, Available here: http://mseafood.vasep.com.vn/panga/724_10857/what-are-biology-characteristics-of-tra-and-basa-fish.htm
2. Seafood Handbook, Available here: https://www.seafoodsource.com/seafood-handbook/finfish/basaswai
3. Fishbase, Available here: http://www.fishbase.us/summary/SpeciesSummary.php?ID=14154&AT=swai
4. Fish Laboratory, Available here: https://www.fishlaboratory.com/fish/swai-fish
5. National Library of Medicine, Available here: https://pubmed.ncbi.nlm.nih.gov/25198598/