Water quality management is the foundation of fish welfare in aquaculture - poor water conditions cause chronic stress, disease, and death.
Fish in poor water quality conditions suffer physiologically at every level - inadequate oxygen causes distress and tissue damage, ammonia toxicity causes neurological impairment, and temperature stress compromises immune function. Poor water quality is associated with increased disease outbreaks, reduced growth, and elevated mortality. Chronic sub-lethal stress from marginal water quality may be more widespread than acute events but is harder to detect and quantify. Investing in water quality monitoring and management infrastructure is both a welfare imperative and economically rational given reduced mortality and disease losses.