Freshwater fish are among the world's most numerous vertebrates and face welfare threats from habitat degradation, pollution, and recreational and commercial fishing.
Wild freshwater fish welfare is a product of habitat quality across enormous geographic scales. Fish in degraded rivers — with elevated temperatures, reduced oxygen, pollution, and physical barriers — experience chronic physiological stress that compromises immunity, reproduction, and survival. Mass mortality events from algal blooms or hypoxia cause acute, large-scale suffering that is visible but often normalised in agricultural landscapes. Recreational catch-and-release fishing, while widely practiced as a conservation-minded alternative to kill fishing, causes measurable physiological stress in fish and impairs post-release survival particularly in warm water conditions. The scale of freshwater fish welfare concerns — affecting billions of individuals across hundreds of thousands of kilometres of waterways — demands policy responses at watershed and national level.