Goldfish and koi are among the most commonly kept fish globally, yet suffer from chronic welfare deficits from inadequate space, water quality, and poor husbandry.
The welfare of ornamental fish is routinely neglected, with goldfish in particular normalized as short-lived, low-need pets despite being capable of multi-decade lives under appropriate conditions. Inadequate water quality from insufficient filtration volume causes chronic ammonia toxicity - a physiological stressor equivalent to air pollution in severity. Overcrowding prevents normal behavior and accelerates water quality deterioration. Fish welfare requires the same attention to species-appropriate environment as any other companion animal.