Lice are a huge problem. If this solution works, it must not be implemented that widely. The news is full of solutions like physical washing, thermic treatment (basically hot baths), loads of chemicals, also huge amounts of chlorine poured into surrounding rivers because the fish escape the farms and spread lice. The lice are really adaptive. There are more and more lice due to higher sea temperatures[0] and increased resistance to treatments.

[0] https://www-nrk-no.translate.goog/nordland/hoye-temperaturer...