Scientific understanding of fish cognition has advanced dramatically in recent decades. Fish can learn, remember, solve problems, use tools and show evidence of pain experience — facts that have profound welfare implications.
The evidence for fish cognition and sentience is now sufficiently strong to demand a fundamental revision of how we treat fish in fisheries, aquaculture, research and the ornamental trade. Fish feel pain, experience fear, form social bonds and exhibit complex behaviour. The fact that this was not previously known — or was dismissed — does not reduce the welfare obligation it creates. Practical implications include anaesthesia for procedures, rapid killing methods in fisheries, enriched environments in aquaculture and research, and recognition of fish welfare in legal frameworks.