The proximate composition and fatty acid (FA) profiles of five Brazilian freshwater fish species, namely Brycon cephalus (BC), Cichla ocellaris (CO), Prochilodus lineatus (PL), Leporinus friderici (LF) and Pseudoplatystoma corruscans (PCO), were investigated. CO and LF exhibited the highest (p < 0.05) moisture content, as well as one of the lowest (p < 0.05) lipid values, whereas BC presented the lowest (p < 0.05) moisture and, alongside PL, the highest (p < 0.05) lipid content. The predominant FAs in the evaluated fish species were palmitic, oleic, linoleic and docosahexaenoic acids. BC and CO presented high n-3 PUFA content, especially DHA, and demonstrated superior nutritional quality indices compared to the other evaluated fish species. Furthermore, a significant relationship was observed among these species, suggesting they possess similar nutritional lipid values. Thus, BC and CO were proven to be an excellent matrix with relevant lipid quality, desirable for human health.