Nile tilapia is one of the most important aquaculture species globally, with welfare challenges in cage systems related to crowding, water quality, and monosex production techniques.
Tilapia welfare in cage systems is challenged by the species social complexity. As cichlids, tilapia establish complex social hierarchies and territorial boundaries that crowding makes impossible to maintain. High stocking densities cause chronic stress, increased aggression, and fin damage. The sex reversal process using methyltestosterone, while reducing aggression in all-male groups, involves early life hormonal manipulation that raises welfare questions. Water quality in heavily stocked cages can deteriorate rapidly in warm water conditions. Welfare-positive tilapia production requires optimised stocking densities and water quality management.