Dissolved oxygen levels in tilapia ponds critically affect fish welfare, with low oxygen causing stress, disease, and mortality.
Chronic suboptimal dissolved oxygen causes physiological stress, immune suppression, and increased disease susceptibility in tilapia. Acute crashes cause mass suffocation, a highly aversive experience. Farmers managing oxygen only to prevent mortality may still expose fish to sustained welfare-compromising hypoxia. Welfare-focused oxygen management maintains levels above stress thresholds throughout the diel cycle.