For P. mesopotamicus and O. niloticus , the dose, exposure time and efficacy observed in this study were satisfactory in controlling of trichodinids. The increase in treatment interval with 50.0 mg L−1 from 1 to 2 hours in pacu resulted in better efficacy. According to Mitchell (1995), time of the treatment is the most important factor when considering the efficacy of a therapeutic treatment1 to 2 hours in pacu resulted in better efficacy. According to Mitchell
(1995), time of the treatment is the most important factor when considering the efficacy of a therapeutic treatment