Striped catfish Pangasianodon hypophthalmus

The striped catfish, farmed as tra or pangasius, is a large migratory catfish of the Mekong, Chao Phraya and Maeklong basins - FishBase gives 130 cm standard length and 44 kg, water of 22 to 26 degrees Celsius and pH 6.5 to 7.5 - that has become one of the most intensively farmed fish in the world, with 3,158,705 tonnes produced in 2024. What makes that intensity possible is physiological: it is a facultative air-breather, so it can be held in deep earthen ponds at densities and dissolved oxygen levels that would kill a strictly gill-dependent species. Vietnamese intensive pond culture on that model produced about 1.5 million tonnes worth roughly USD 1.7 billion in 2020, concentrated in a few Mekong Delta provinces. Wild fish migrate upstream to spawn between May and July, so captive broodstock are spawned artificially. The disease that defines the industry is bacillary necrosis of pangasius, caused by Edwardsiella ictaluri - the same organism behind enteric septicaemia in North American channel catfish - which can kill up to 90 per cent of an affected population. Across twenty years of Vietnamese isolates, 81 per cent carried resistance genes spanning ten antibiotic classes, so treatment must follow isolation and susceptibility testing rather than habit.