Cleaner Fish for Salmon Lice: Welfare of Wrasse and Lumpfish

Cleaner fish — wrasse and lumpfish — are widely used in salmon farming to control sea lice. Their welfare has become a major concern as millions are deployed each year with minimal oversight.

Key Facts

Sea lice (Lepeophtheirus salmonis and Caligus spp.) are parasites that cause significant welfare problems and economic losses in salmon farming.
Cleaner fish are used as a biological control method — they eat sea lice off farmed salmon.
Wrasse species (ballan, goldsinny, corkwing) and lumpfish (Cyclopterus lumpus) are the two main cleaner fish types.
Approximately 50-60 million cleaner fish are used annually in Norwegian salmon farming alone.
Cleaner fish suffer high mortality rates in salmon pens — often 50-80% within a production cycle.
Causes of cleaner fish mortality include predation by salmon, disease, poor nutrition, and inappropriate environmental conditions.
Welfare standards for cleaner fish are poorly developed; they are often not counted in mortality reporting for net pens.

Welfare Considerations

Cleaner fish — particularly wrasse — are sentient animals with complex social behaviors and specific ecological needs that are not met in salmon production pens. Lumpfish are pelagic fish placed in environments they would not naturally inhabit. Both suffer high mortality, often from being eaten by the salmon they are meant to clean, disease exposure, and nutritional deficiencies. The ethical paradox is stark: cleaner fish are used to improve the welfare of salmon, but suffer significantly in the process. The industry's rapid scaling of cleaner fish use has far outpaced welfare science and regulatory frameworks. Developing better welfare standards, reducing reliance on cleaner fish through alternative lice control methods, and improving survival rates are all urgent welfare priorities.

What You Can Do

Support research into alternative sea lice control methods that do not rely on cleaner fish (e.g., snorkel barriers, laser delousing).
Advocate for cleaner fish welfare standards and their inclusion in aquaculture welfare monitoring and mortality reporting.
Choose salmon from producers who have committed to minimising cleaner fish mortality and use.
Reduce salmon consumption from conventional aquaculture systems and choose alternatives with better environmental and welfare credentials.
Support welfare science research on wrasse and lumpfish biology, sentience, and needs.
Encourage regulatory bodies to extend meaningful animal welfare protections to all fish used in aquaculture.