Tilapia are the second most farmed fish globally, with welfare concerns including crowding stress, oxygen depletion, and aggressive hierarchical behaviour in dense production systems.
Tilapia welfare in aquaculture is shaped by the trade-off between their relative physiological hardiness and the welfare harms that accompany high-density production. Their ability to survive in degraded water quality conditions has sometimes been used to justify poor management, but surviving degraded conditions is not the same as thriving in appropriate ones. High stocking densities cause chronic aggression as dominant fish exclude subordinates from feed; injuries from fighting are common. Water quality management that maintains adequate oxygen and removes waste is both a welfare requirement and a production efficiency measure.