Cleaner fish including wrasse and lumpfish are used to control sea lice on farmed salmon - their welfare has been largely neglected despite being vertebrates with pain receptors and complex behaviours.
Cleaner fish welfare represents a significant gap in aquaculture welfare standards. These fish are vertebrates capable of pain and suffering, yet have been treated primarily as biological tools. The extreme mortality rates in salmon cages indicate systematic welfare failure - fish dying in large numbers from stress, starvation, predation and disease. Welfare improvements include providing appropriate refugia, supplemental feeding, age-appropriate stocking rates and monitoring cleaner fish health as carefully as salmon health. The welfare of hundreds of millions of cleaner fish annually deserves integration into salmon welfare certification alongside salmon welfare measures.