<p>This study evaluated the reproductive parameters of yellowtail tetra (<i>Astyanax altiparanae</i>) fed with aflatoxins and growth rates and reproductive performance of progeny. Female reproductive parameters, including gonadosomatic index (GSI), egg volume (EV), and fertilization rate (FR), were significantly reduced in groups fed with AB₁ compared to the control. Non-contaminated females had a mean GSI of 9.19%, while those exposed to 10, 20, and 50 μg/kg of aflatoxins showed reduced GSIs of 4.78%, 4.12%, and 3.35%, respectively. The present study revealed a significant reduction in EV was observed in females exposed to aflatoxin-contaminated diets. Regarding the FR, the control diet presented 91.40%, whereas those of the diets containing 10, 20, and 50 µg/kg aflatoxins were 76.40%, 87.77%, and 88.40%, respectively. In contrast, male reproductive parameters, including sperm concentration, motility, and motility duration, were not significantly affected, suggesting a possible sex-specific sensitivity to aflatoxin. Hepatosomatic (HSI) and viscerosomatic (VSI) indices did not vary significantly among treatments in either sex. No significant differences in growth rates and reproductive parameters were observed in the F1 generation. These findings underscore the importance of establishing strict regulatory limits for aflatoxins in aquafeeds to safeguard fish reproductive health and ensure the sustainability of aquaculture production.</p>