Tilapia is one of the most farmed fish globally, particularly in developing countries. Their welfare in intensive aquaculture systems is poorly monitored despite growing evidence of their capacity for suffering.
Tilapia welfare is often dismissed on the basis that these fish are "tough" — capable of surviving in poor water quality conditions. But survival under stress does not indicate absence of suffering. Chronic hypoxia in overcrowded ponds causes measureable stress and physiological harm. Live transport in densely packed containers causes exhaustion and injury. Hormonal sex reversal, while not necessarily painful, raises ethical questions. The scale of tilapia production means that even minor per-animal welfare improvements across better-managed farms would benefit enormous numbers of individual fish.