The invention relates to a method for removing a parasite, such as ectoparasite from a marine organism, using a system comprising a treatment chamber (22, 24'), said treatment chamber (22, 24') comprising a treatment portion (6, 10') and a water portion (7, 11') containing water or seawater, said treatment portion (6, 10') comprising a liquid treatment mixture having a density less than the water or seawater in the water portion (7, 11') such that the treatment portion (6, 10') is situated above the water portion (7, 11') in the treatment chamber (22, 24'). The method comprising the sequential steps of separating water/seawater from the marine organism (30), dropping the marine organism (30) into the treatment mixture from an elevation above the treatment portion (6, 10'), guiding the marine organism (30) through the treatment portion (6, 10') for treating of parasite attached to the marine organism (30), and further into the water portion (7, 11'), guiding the marine organisms towards an outlet (8a, 12') situated in the lower part of the treatment chamber (22, 24') below the treatment portion (6, 10'). The invention further relates to a system for removing the parasites from a marine organism.
