Home aquarium fish are among the most commonly kept companion animals but their welfare needs are often poorly understood. Water quality, appropriate species selection, and space provision are critical to fish welfare.
Aquarium fishkeeping at its best provides appropriate environments where fish can express natural behaviours, maintain good health, and live full lifespans. At its worst, it causes chronic welfare deficits through inadequate water quality, inappropriate species combinations, and housing that fails to meet fundamental space and social needs. The welfare of aquarium fish is rarely considered alongside that of more familiar companion animals, but fish experience stress and have welfare-relevant responses to poor conditions. Improving aquarium fish welfare requires better consumer education, honest labelling about species requirements, and a shift toward captive-bred rather than wild-caught sources.