Fish kept as pets deserve welfare consideration; most suffer from inadequate tank size, water quality, and environmental complexity based on current husbandry practices.
Fish in inadequate tanks experience chronic stress from inappropriate water chemistry, temperature, and social conditions. The myth that fish have short memories has been thoroughly disproven — goldfish show preferences and learning that require memory. Bettas in small, barren containers cannot exhibit natural territory-holding and exploration behaviour. Cichlids in incompatible social groups experience chronic aggression. Providing appropriate conditions requires significant research before purchase.