Goldfish are among the most commonly kept pets yet are routinely housed in conditions that cause significant welfare compromise, from oxygen depletion to social isolation.
Goldfish kept in bowls or undersized tanks suffer from oxygen depletion, ammonia toxicity, stunted growth from cramped conditions, and chronic stress. These fish demonstrate learning abilities and pain responses comparable to other vertebrates, making their welfare a serious ethical concern. Properly housed goldfish display active, exploratory behaviors.