Evidence of play behaviour and sophisticated cognition in fish challenges traditional assumptions about their capacity for welfare-relevant experiences and has significant implications for how they are treated.
The traditional view of fish as reflex-driven, cognitively simple animals has been substantially revised by decades of behavioural and neurological research. Fish demonstrate learning, memory, social learning, individual recognition, and in some species, apparent play — all behaviours associated in other taxa with positive welfare experiences and the capacity for suffering. This has direct welfare implications: if fish can experience positive states, they can also suffer negative ones, and this should inform how they are housed, handled, transported, and killed. Aquaculture welfare standards are slowly incorporating fish behavioural needs, and consumer awareness of fish cognition is growing. The challenge is to translate scientific understanding into policy and practice at the scale of global fisheries and aquaculture.