Fish kept in home aquariums are often assumed to have minimal welfare needs, but growing evidence of fish cognition and sentience challenges this assumption and supports more enriched tank environments.
Aquarium fish welfare suffers from a persistent underestimation of fish intelligence and capacity for suffering. Many aquarium fish are kept in tanks far too small for their species, with insufficient filtration, wrong water chemistry, or inappropriate companionship. Bettas kept in small vases, goldfish in bowls, and cichlids without sufficient territory all experience chronic stress. Providing enrichment through planted environments, substrate for digging species, and appropriately sized social groups significantly improves fish welfare. Regular water quality testing and maintenance are more important to fish welfare than any other single factor.