Fish pain science has advanced significantly over the past two decades. Evidence that fish experience pain and suffering has direct implications for how they are treated in research settings.
The scientific evidence that fish experience pain and can suffer is now sufficiently strong to require that fish welfare in research be taken seriously rather than dismissed based on assumptions about neural complexity. Fish do not have a neocortex but possess functional equivalents that enable nociception and aversive learning. The behavioral responses of fish to painful stimuli, and their attenuation by analgesics, provide compelling evidence that fish experience something analogous to pain. Applying the 3Rs framework rigorously to fish research requires refinement of procedures to minimize pain and distress, use of appropriate analgesia for painful procedures, and humane endpoints that recognize fish behavioral indicators of suffering. The regulatory lag behind the science means that welfare improvements in fish research require institutional initiative beyond minimum legal requirements.