Rainbow trout are the most widely farmed salmonid globally outside of Atlantic salmon, with well-studied welfare needs and established science on pain, fear, and stress responses.
Rainbow trout are welfare-significant in multiple senses: they are widely farmed, their sentience is scientifically well-established, and the welfare science base for their care is more advanced than for most farmed fish. The translation of this science into regulatory standards and farm practice has been inconsistent. Best-practice rainbow trout farming combines appropriate stocking densities, good water quality management, enrichment structures, disease prevention, and humane electrical stunning before slaughter. Consumer demand for certified higher-welfare trout and regulatory minimum standards both drive improvement.