Pangasius (Basa) from Vietnam and catfish from the US South are among the most intensively farmed freshwater fish. Their welfare in large-scale pond systems deserves attention.
Pangasius farmed in the Mekong Delta are often held at extremely high densities in river-based cages or ponds. Despite their physiological tolerance for poor conditions, high density causes aggression, disease, and stress. Harvest involves draining ponds and collecting fish by hand or net — a highly stressful process during which fish may be left in air for extended periods. Antibiotic overuse to manage disease in crowded conditions is an ongoing concern. US catfish are typically stunned electrically or by CO2 before slaughter, representing a welfare improvement over many Asian systems. Welfare certification schemes for pangasius are emerging but inconsistently applied.