Teflubenzuron (TFB) is an insecticide derived from urea;it has a regulatory action on the growth of arthropods and crustaceans and has been used against Lepeophtheirus salmonis and Lernanthropus kroyeri However, the anti-protozoan effects of this drug have not yet been described in the literature. The aims of this research were to determine the acute toxicity of the TFB in O. niloticusand P. mesopotamicusand to treat both species with trichodinids protozoan in laboratory conditions.