Iridescent Shark

The fish is named for the glow or iridescence exhibited in juveniles, as well as the shark-like appearance of this and other shark catfish.

Orange: March to May Dark green: May to September Red: October to February Shaded region: spawning region of the southern Mekong population between Khone Falls and Kratie]] Iridescent sharks originate in the large rivers Chao Phraya and Mekong in Asia, though they have been introduced into other rivers for aquaculture. They are a freshwater fish that natively live in a tropical climate and prefer water with a 6.5–7.5 pH, a water hardness of 2.0–29 dGH, and a temperature range of . They can tolerate hypoxic conditions thanks to their swim bladder which can be used as an air-breathing organ. They prefer large bodies of water similar to the deep waters of their native Mekong river basin. The iridescent shark is a migratory fish that in most regions moves upstream to spawn during the flood season while the waters are high and returns downstream to seek rearing habitats when the river water levels recede. The dates of the migrations vary depending on the river system. In the Mekong river basin, they migrate upstream in May to July and return downstream during September through December. South of the Khone Falls, upstream migration occurs in October to February, with its peak in November to December; here, it appears to be triggered by receding waters at the end of the flood season. Disruption to these sharks can come from many physical stressors, including but not limited to shear forces, rapid decompression, blade strike and turbulence. These can lead to and have led to an increase in the Injury and mortality rate of these sharks. This is a sad reality since these injured can be caused by hydropower developments which are being put into place to combat the global climate crisis that is being faced. Iridescent sharks are also introduced to other Southeast Asia countries for food, especially Peninsular Malaysia, Singapore, Indonesia and Myanmar. In Malaysia, Singapore and Indonesia they are called ikan patin (which 'ikan' means fish in Malay and Indonesian), Malaysian Chinese prefer them steamed or cooked in whole, while Malay prefer cooking these fishes with Tempoyak and curry. In Thailand, swai fish are commonly found in rivers and canals that run past important Buddhist temples or waterside places. Swai live in large schools, sometimes with other fish such as spot pangasius and red-tailed tinfoil with tinfoil barb. Fish that live in that area, people won't catch them, and often feed them (usually bread), which is considered a merit-making and fun activity.

Pangasius does not have a gourmet reputation and is sold cheaply as swai (, from Thai สวาย s̄wāy) in the United States, panga (or pangas) in Europe and cream dory and basa in several Asian countries and in Australia and the UK. Despite its lowly reputation, the total export of pangasius from Vietnam reached US$1.8 billion in 2014. Pangasius fillets are an increasingly popular product because of their low cost, mild taste and firm texture. Recipes for other whitefish such as sole or halibut can be adapted to pangasius. Pangasius is an omnivorous fish, and thus does not require a high level of animal protein in its diet. Typical grading sizes are , , and .

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, Iridescent sharks require a minimum tank size of to develop naturally. Schools require even larger tanks. If given enough room and fed adequately, they can reach in length. In most home aquaria, the lack of space stunts their growth. For this reason, most iridescent sharks kept in home aquaria grow to in length only and may die prematurely. When provided adequately sized aquaria and proper husbandry, iridescent sharks may live into their teens and grow to full size.