Pet fish are among the most commonly kept animals yet receive the least welfare attention, with tank size, water quality, and social needs frequently unmet by uninformed owners.
Pet fish welfare is neglected both by individual owners and by regulatory systems that exclude fish from most animal welfare protections. The casual nature of fish acquisition — impulse purchases, fairground prizes, gifts — results in fish being kept in wholly inadequate conditions by well-meaning but uninformed owners. Fish in undersized, uncycled tanks suffer from poor water quality that causes physiological stress equivalent to chronic disease. Social species kept alone suffer the welfare costs of isolation. The research demonstrating fish pain and sentience makes this ongoing welfare neglect difficult to justify. Informed fishkeeping, species-appropriate tank sizes, proper filtration and cycling, and sourcing from captive-bred stocks rather than wild-caught are the foundations of responsible fishkeeping.