The scientific understanding of fish welfare has advanced dramatically in recent decades, reshaping how we think about pain, suffering, and the ethics of fish use.
Fish welfare science has undergone a paradigm shift: from a default assumption that fish cannot suffer to an evidence-based recognition that fish are sentient animals with genuine welfare needs. This shift has profound ethical implications for aquaculture, fisheries, and the scientific use of fish. The welfare science community now broadly accepts that fish experience pain and stress, although the nature and intensity of these experiences remains an active area of research. Translating this understanding into practical welfare improvements for the billions of fish in aquaculture and the trillions harvested from wild fisheries is the central challenge of applied fish welfare science. The development of welfare indicators, assessment tools, and husbandry standards for fish is progressing but requires sustained research investment and regulatory attention.