Lumpfish (lumpsucker) are used as cleaner fish in salmon farms to eat sea lice. Their welfare as working animals in aquaculture is a largely unrecognised concern.
Lumpfish welfare represents an almost invisible welfare concern: fish used as a tool by another industry, with their own welfare needs substantially overlooked. These are sentient fish with pain responses and stress physiology - they experience the conditions of salmon sea pens despite not being the commercial target species. High mortality rates of lumpfish within salmon production cycles suggest significant welfare compromise. The welfare of cleaner fish has received growing research attention in recent years, but practical implementation of improved welfare standards lags far behind the scale of their use.