Water quality parameters — oxygen, ammonia, pH, and temperature — are fundamental determinants of fish welfare in aquaculture, yet monitoring and management remain inadequate in many facilities.
Water quality is to fish welfare what air quality is to terrestrial animal welfare — the most fundamental environmental determinant of health and positive experience. Fish in poor water quality suffer physiologically and behaviorally, experiencing the equivalent of chronic respiratory stress, toxic exposure, and thermal discomfort. Yet water quality monitoring in aquaculture remains inconsistent, and many regulatory frameworks focus on production metrics rather than welfare-relevant parameters. Welfare standards for aquaculture should specify minimum acceptable ranges for dissolved oxygen, ammonia, carbon dioxide, and temperature appropriate to each species.