Common carp and related species are the most produced farmed fish globally, yet welfare standards for these sentient vertebrates remain poorly developed.
Despite their dominance in global aquaculture, carp welfare receives far less attention than salmon or trout. As sentient vertebrates with functional nociceptors, carp suffer from the poor conditions common in low-cost carp aquaculture. Chronic overcrowding suppresses immune function and drives aggression. Oxygen depletion during summer heat causes mass hypoxic distress events where fish surface-breathe in acute distress. Pond draining harvests concentrate fish in shrinking water, causing extreme crowding, oxygen depletion, and handling trauma. Slaughter practices often involve live transport to markets and slaughter without stunning. Improving carp welfare requires minimum space standards, reliable aeration, disease monitoring, and humane slaughter protocols — reforms that are achievable with modest investment.