Rapidly advancing fish cognition research is transforming understanding of fish mental lives and the welfare implications of how we treat them.
Fish cognition research has fundamentally challenged the assumption that fish are simple, reflexive animals with minimal capacity for suffering or complex experience. Mirror self-recognition tests, episodic memory demonstrations, tool use, social information processing, and cognitive bias studies collectively paint a picture of cognitive complexity far exceeding traditional assumptions. This has direct welfare implications: if fish have more sophisticated cognitive lives than previously assumed, the suffering they experience in suboptimal aquaculture conditions, during catch-and-release angling, or in aquarium environments may be richer and more significant than previously considered. The welfare science is catching up with the cognition science, developing validated indicators of fish welfare states that enable evidence-based management improvements. Precautionary approaches to fish welfare are increasingly scientifically justified.