Fish welfare has been defined in a variety of different ways, often relating to the level of environmental challenge fishes face. For fishes held in captivity, stressors such as handling, transport, water quality, stocking density, housing conditions and disease can induce a physiological stress response resulting in poor welfare. In recent years, particularly for food-fishes, the importance of how we measure fish welfare has been highlighted, including the development of operational welfare indicators. Promoting improved and positive fish welfare is likely to lead to healthier fishes with benefits both for fish welfare and also humans.