Pangasianodon is a genus of large shark catfish in family Pangasiidae, native to the Mekong and Chao Phraya basins of Cambodia, Laos, Thailand, and Vietnam. The atlas's two species span an extraordinary size range, from roughly 51 in up to 118 in, reflecting genuinely different life histories rather than one typical body plan. Both are big-river fish: streamlined, forked-tailed, downturned-mouthed catfish built for cruising open, silty water rather than hugging cover.
The two species could hardly diverge more in aquarium relevance. Pangasianodon hypophthalmus, the iridescent shark, is one of the most widely sold juvenile catfish in the trade - a sleek, silvery fish that is often bought small and later outgrows all but the largest home aquaria or ponds, a mismatch that causes real welfare problems down the line. Pangasianodon gigas, the Mekong giant catfish, is a different story: Critically Endangered, among the largest freshwater fish alive, and essentially never kept - its conservation, tied to Mekong dam-building and fishing pressure, is a matter for river management rather than the hobby.
Both species are migratory big-river fish, historically undertaking long spawning migrations along the Mekong mainstem in response to the seasonal flood pulse, a pattern now badly disrupted by dam construction across the basin. The Mekong giant catfish in particular has become a flagship for Mekong conservation, with captive-breeding and restocking efforts aimed at supplementing a wild population that has collapsed over recent decades.