Iridescent shark

The iridescent shark (Pangasianodon hypophthalmus) is a shark catfish that is a native to the rivers across Southeast Asia. They are not really sharks. They do, however, look very similar to small sharks. They are found over Mekong Basin and the Chao Phraya River areas and used for food there. The fish are marketed as swai in the United States. They are very similar to the US catfish. The meat is often marketed under the common name swai (from Thai สวาย).

It has also been introduced into other river basins as a food source, and its striking appearance and iridescence have made it popular with fishkeeping hobbyists, among whom it is also known as the Siamese shark catfish or sutchi catfish.

Description

Adults reach up to 130 cm (4.3 ft) in length and can weigh up to a maximum of 44 kg (97 lb). They have a shiny, iridescent color that gives these fish their name. However, large adults are uniformly gray. The fins are dark gray or black. Juveniles have a black stripe along the lateral line and a second black stripe below the lateral line.

Distribution

Iridescent sharks originate from the large rivers Chao Phraya and Mekong in Asia, though they have been introduced into other rivers for aquaculture.

Culinary profile

Pangasius does not have a gourmet reputation and is sold cheaply as swai (/swaɪ/, from Thai สวาย s̄wāy) in the United States, panga (or pangas) in Europe and cream dory and basa in several Asian countries and in the UK.

Diet and behavior

The iridescent sharl is an omnivorous species, and thus does not require a high level of animal protein in its diet. Typical grading sizes are 3–5 oz (85–140 g), 5–7 oz (140–200 g), and 7–9 oz (200–260 g). Its diet consists of other fish, plant matter, and crustaceans.

Also, these fish are fast enough to catch and eat even active fish like tetra fish and guppies.

In the aquarium

While juvenile iridescent sharks are sold as pets for home aquariums, they are not easy fish to keep. Iridescent sharks are schooling fish that prefer groups, are accustomed to living in rivers, and are active fish that require space. Iridescent sharks require a minimum tank size of 12 m (39 ft) to develop naturally. Schools require even larger tanks.

References

1. Vidthayanon, C.; Hogan, Z. (2011). "Pangasianodon hypophthalmus". IUCN Red List of Threatened Species. 2011: e.T180689A7649971. doi:10.2305/IUCN.UK.2011-
2. "Appendices | CITES". cites.org. Retrieved 2022-01-14.
3. Axelrod, Herbert, R. (1996). Exotic Tropical Fishes. T.F.H. Publications. ISBN 0-87666-543-1.
4. "Status of the Mekong Pangasianodon Hypophthalmus Resources, with Special Reference to the Stock Shared Between Cambodia and Viet Nam". Mekong River Commission. July 12, 2002 – via Google Books.

Other websites

• Planet Catfish
• Iridescent Shark (Pangasionodon hypophthalmus) Care Sheet

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