Koi are ornamental carp kept in garden ponds and traded as high-value fish. Their welfare in ponds, shows, and the competitive koi trade raises important considerations.
Koi shows involve capturing fish from their home ponds, transporting them in sealed bags or vats for hours, and displaying them in show tanks under intense lighting for multiple days — a highly stressful experience for social fish adapted to stable pond environments. Transport stress is a significant cause of koi mortality. High-value koi are frequently over-handled for health checks, photography, and showing. Pond koi face welfare challenges from predator stress (herons), temperature extremes, and disease. Koi herpesvirus outbreaks cause severe, often fatal disease. Very large koi in small ornamental ponds cannot express natural foraging and swimming behaviour.