The ornamental fish trade involves an estimated 1-2 billion fish annually from over 4,000 freshwater and marine species, representing significant welfare challenges throughout the supply chain. Wild-caught marine species (clownfish, tangs, angelfishes) face capture trauma from cyanide stunning in some source countries, transport mortality of 20-50% from point of capture to retail, and placement in aquaria where species-specific needs cannot be met. Freshwater species are predominantly captive-bred, improving welfare at source but still subject to stressful transport conditions. Retail fish welfare is highly variable: inadequate tank volume, inappropriate species mixing, and poor water quality create chronic stress. Consumer welfare education is limited; impulse purchasing leads to inadequate care. Welfare improvements include cyanide-free certification programmes, improved transport protocols (lower density, oxygen supplementation, anaesthetic use for long journeys), and retailer welfare standards. The Marine Aquarium Council (MAC) certification programme sets sourcing and handling standards.