Fish welfare science has historically focused on preventing negative states such as pain and stress. A growing movement aims to identify and promote positive welfare indicators - signs that fish are thriving, not merely surviving.
The shift from welfare as 'absence of suffering' to welfare as 'presence of positive states' represents a conceptual advance that significantly raises the bar for what we should expect from animal husbandry. Applied to fish, this means asking not just whether fish are avoiding pain and extreme stress, but whether they have opportunities for exploration, social interaction, and behavioral expression consistent with their species needs. Positive welfare thinking reframes enrichment from a luxury to a necessity, and challenges production systems to demonstrate that fish can express behavioral indicators of positive states, not merely survive without obvious suffering.