Carp are the most widely farmed fish globally by volume, yet receive little welfare attention despite clear evidence they can experience pain and stress.
Carp welfare represents the largest numerically underserved welfare population in aquaculture — more carp are farmed than any other species, yet they receive minimal welfare attention in research, regulation and certification. The assumption that carp hardiness implies welfare resilience conflates survival with wellbeing. Carp show cortisol stress responses, behavioral changes to aversive stimuli and pain avoidance behaviors comparable to species receiving more welfare attention. The scale of carp production means that even modest welfare improvements at the industry level would benefit an enormous number of fish. Species-specific welfare standards development, research investment and regulatory inclusion represent urgently needed actions.