Some good news since this post was written a few years ago: the usage of cleaner fish in Norway has declined from a peak of 60 million in 2019 to 24 million in 2024.[1] From what I’ve read this seems to be due to both pressure from the media and Norwegian authorities[2] and also growing use of other methods like laser delousing, which showed positive results in a recent study.[3] (I wasn’t able to tell how important each factor was in causing this decline.)
More good news is that the country with the second largest salmon industry, Chile, has not started using cleaner fish:
The species used in Norway are banned in Chile because they’re not native there.[4]
It was reported in 2018 that species native to Chile were being trialed use on Chilean salmon farms.[5]
However, a 2023 article says “In both cases, preliminary trials [2015-2019] have been unsuccessful”.[6]
For example “The Norwegian Council for Animal Ethics [an independent advisory body] has stated that continuing the use of cleaner-fish is not justifiable.” (from the Norwegian Veterinary Authority Fish Health Report 2024, p. 96.), or public criticism from the Norwegian Food Safety Authority.
Some good news since this post was written a few years ago: the usage of cleaner fish in Norway has declined from a peak of 60 million in 2019 to 24 million in 2024.[1] From what I’ve read this seems to be due to both pressure from the media and Norwegian authorities[2] and also growing use of other methods like laser delousing, which showed positive results in a recent study.[3] (I wasn’t able to tell how important each factor was in causing this decline.)
More good news is that the country with the second largest salmon industry, Chile, has not started using cleaner fish:
The species used in Norway are banned in Chile because they’re not native there.[4]
It was reported in 2018 that species native to Chile were being trialed use on Chilean salmon farms.[5]
However, a 2023 article says “In both cases, preliminary trials [2015-2019] have been unsuccessful”.[6]
Rethink Priorities, 21 November 2025: Mapping salmon welfare: sea lice treatments. (Thanks to @Hannah McKay🔸 and @Sagar K Shah for your work.)
For example “The Norwegian Council for Animal Ethics [an independent advisory body] has stated that continuing the use of cleaner-fish is not justifiable.” (from the Norwegian Veterinary Authority Fish Health Report 2024, p. 96.), or public criticism from the Norwegian Food Safety Authority.
Fishfarmingexpert, 1 September 2025: Significantly fewer treatments needed at farms with lice lasers. The study says “Sites with optical delousing used on average fewer cleaner fish.” You can see what the laser system looks like in operation in this video.
Thefishsite, 30 Nov 2018
Sánchez et al, 2018: The Patagonian blenny (Eleginops maclovinus): a Chilean native fish with potential to control sea lice (Caligus rogercresseyi) infestations in salmonids
Bravo and Treasurer, 2023: The management of the sea lice in Chile: A review