Rainbow trout is the most important farmed freshwater fish in the UK, and welfare standards are increasingly scrutinised by retailers and certification bodies.
Rainbow trout welfare in UK farms is increasingly supported by industry-led welfare codes and third-party certification. However, compliance and enforcement vary, and climate change is creating new welfare challenges as summer water temperatures exceed thermal comfort thresholds more frequently. Stocking density is the most consistently monitored welfare indicator, but gill health, fin condition, and abnormal behaviour such as surface-skimming also provide important welfare information. Pre-slaughter stunning using electrical or carbon dioxide systems is now standard in most UK operations, substantially improving slaughter welfare compared to ice slurry methods.