Koi and goldfish kept in garden ponds require careful water quality management and veterinary care to maintain health and welfare.
Koi and goldfish are often underestimated as welfare subjects, yet they are long-lived, cognitively capable fish that suffer significantly in poor conditions. Ammonia and nitrite spikes from overcrowding or inadequate filtration cause chemical burns to gills, stress, and immune compromise. Ulcer disease, a common consequence of poor water quality or injury, causes open wounds that fish carry for months if untreated. Herpes viral infections have caused catastrophic losses in poorly managed collections. Responsible pond keeping requires investment in adequate filtration, regular water testing, appropriate stocking densities, and access to fish veterinary expertise.