From top: holding tank for Pangasius of harvestable size; fins are cut off, gills removed to bleed fish; fish is deftly cut with fillet knife; entrails are removed; choice cut. The remaining bony part which includes head is cut for paksiw, or for animal food.
It is called iridescent shark, Pangasius hypophthalmus, but it is not a shark, it is a catfish related to our hito or paltat (Ilk). It is also known as Siamese shark or sutchi catfish, or striped catfish, and dory fish. The species is found in Southeast Asia, in the Mekong (Vietnam) basin as well as the Chap Phraya (Thailand) where and is commercially raised for food. It has also been introduced into other river basins as a food source and is common in the fish keeping hobby. It is named for its glow or iridescence exhibited in juveniles. It is omnivorous, feeding on algae, plants, crustaceans and other fish.
The fins are dark grey or black. Juveniles have a black stripe along the lateral line and a second black stripe below the lateral line; they have a shiny, iridescent color that gives these fish their name. However, large adults are uniformly grey and lack the striping. Adults reach up to 130 cm (4 ft) in length and can weigh up to a maximum of 44 kg (97 lb).