Aquarium fish are among the most commonly kept pets globally, yet their welfare is frequently compromised by undersized tanks, poor water quality, inappropriate companions, and disease.
Aquarium fish welfare suffers from several systemic problems. Wild-caught marine fish including clownfish and tangs are often collected using sodium cyanide that stuns fish for easy capture but damages their livers and leads to delayed death. Betta fish displayed and sold in tiny unfiltered cups develop chronic stress from poor water quality. Goldfish and other fish sold as fair prizes are placed with unprepared owners. New Tank Syndrome from inadequate biological filtration causes painful ammonia toxicity. Inappropriate fish combinations lead to predation and stress. Tropical fish kept below their temperature requirements develop immune suppression. Fish welfare in aquariums requires adequate space, appropriate water chemistry, suitable tank mates, and hiding spaces.