The biomass of rotifers is used as live food in aquaculture; their quality is determined by the content of the main polyunsaturated fatty acids and the weight it acquires over time. The objective of this work was to evaluate the variables involved in this process to achieve higher quality. Within the rotifer culture, the following evaluations were carried out nine times (0, 12, 24, 48, 72, 96, 120, 144, 168 hr); with two types of food TRA = 0 (Nannochloropsis oceanica) and TRA = 1 (N.oceanica + Isochrysis galbana); assessing three types of fatty acids (μg/g) eicosapentaenoic (EPA; 20:5nÀ3), docosahexaenoic (DHA; 22:6nÀ3), and arachidonic (ARA; 20:4ωÀ6); and biomass weight in grams from 7,000 individuals per sample. The results showed that the maximum biomass weight was 77.5 g at 96 hr with the mixed treatment.In both treatments, the EPA and DHA fatty acid content exhibited the exact same temporal pattern, while ARA fatty acid was recorded during the entirety of the mixed treatment.The relationship of biomass weight over time versus the fatty acids exhibited significant differences in the mixed treatment, where an increasing trend over time is observed.