Millions of tropical fish are kept in home and public aquaria. Their welfare is frequently overlooked due to misconceptions about fish sentience, yet they have complex needs that are often unmet.
Aquarium fish welfare sits at an intersection of misconceptions about fish sentience and the complexity of maintaining suitable aquatic environments. The assumption that fish "don't feel pain" or have no significant welfare needs is not supported by the evidence — fish show nociceptive responses, stress physiology, and behavioural indicators of suffering that are well-documented. In practice, welfare failures in home aquaria are common: tanks too small for the species kept, incorrect water chemistry, inappropriate tankmate combinations leading to chronic aggression or predation, and disease from poor water quality. The ornamental fish trade also involves significant welfare losses at source: cyanide collection, transport mortality, and the removal of animals from complex reef ecosystems that they were adapted to.