Tilapia is one of the most widely farmed fish globally, with production methods ranging from extensive pond culture to intensive recirculating systems that create specific welfare challenges for these social, territorial fish.
Tilapia welfare in intensive production systems is compromised primarily by high stocking density, which drives the chronic aggression that is natural in territorial species but becomes pathological in crowded conditions. Fish that experience repeated aggressive encounters show elevated cortisol, fin damage, and reduced growth — clear indicators of welfare harm. Hormonal sex reversal of fry, used to produce all-male populations with better growth, involves exposure of developing fish to methyltestosterone; its welfare implications are not fully characterised. As with other farmed fish species, the welfare case is strengthened by growing evidence of fish nociception and stress responses. Improving tilapia welfare requires better stocking density standards, effective slaughter protocols, and integration of welfare indicators into certification and monitoring programmes.