The objective of this research was to evaluate the growth performance, oxidative stress, and fatty acid profiles of lambari (Astyanax altiparanae) fed diets containing different lipid sources: soybean oil, linseed oil, and freshwater fish residue oil combined or otherwise with sesame oil (SEO). The fish (mean weight 0.95±0.46 g; mean length 4.21±2.77 cm) were distributed into 24 cages (cage capacity: 0.70 m 3 ; fish density: 276 individuals m −3 ) in six treatments and four replicates. After 80 days of feeding, they were weighed, and samples were collected for assay of catalase, glutathione reductase (GR), and lactate dehydrogenase (LDH) enzyme activities in muscle and analysis of the fatty acid profiles of polar and neutral fractions of whole eviscerated fish. The addition of SEO reduced docosahexaenoic acid (C22:6n-3, DHA) levels but increased the percentage of highly unsaturated n-3 fatty acids and the DHA: eiocosapentaenoic acid ratio, while reduced GR and LDH enzyme activities in muscle. Thus, certain blends of oils added to fish diets can improve the lipid profile of lambari and protect consumers against reactive oxygen species. How to cite: Natori, M. M.; Oliveira, R. H. F.; Parisi, G.; Bonelli, A.; Melo, M. P. and Viegas, E. M. M. 2019. Oil blends with sesame oil in fish diets: oxidative stress status and fatty acid profiles of lambari. Revista Brasileira de Zootecnia 48:e20170240.