Several types of therapeutic agents have been used in treatments against protozoan in fish farming. Madsen et al.tested 30 substances against Trichodina jadranicaon eel (Anguilla anguilla). Acriflavin , bitionol , Detarox AP®, fresh squeezed raw garlic, malachite green, potassium permanganate and Virkon PF® Vet were 100% effective. However, Chloramine T and potassium permanganate were toxic to eels on therapeutic concentrations, even being totally or partially effective. Balta et al. (2008) also observed formaldehyde and potassium permanganate efficacy against Trichodina spp.