Common carp are among the most widely farmed freshwater fish in Europe and Asia. Their welfare in pond and intensive recirculating systems is increasingly studied by researchers.
Carp welfare varies enormously across farming systems. Traditional extensive pond culture in Central Europe allows relatively natural behavior at low densities, but harvest involves seine netting, prolonged crowding, and transport under stressful conditions. The live sale tradition in many countries — where carp are sold alive at Christmas markets and kept in home bathtubs for days before killing — causes significant suffering through crowding, handling stress, and often inhumane home slaughter methods. CO2 stunning followed by spiking or bleeding is more humane than common alternatives including knife cuts to gills or hitting with blunt objects. Intensive RAS carp farming introduces the welfare challenges of crowding and chronic stress common to intensive fish culture. Research on carp pain processing shows clear nociception supporting welfare-relevant experience.