This study was carried out to investigate the effects of enriched Artemia with selenium nanoparticles on growth and survival indices and biochemical factors in Poecilia reticulata larvae over a six-week period. Guppy fish larvae with a mean weight of 33.55 mg in three treatments and one control group (each with three replicates) were fed with Artemia franciscana enriched with 5, 10, and 50 mg/L selenium nanoparticles. In terms of growth indices, significant differences were observed among treatments in length increment, weight gain, specific growth rate and survival rate (P 0.05). Regarding biochemical factors, significant differences were observed between treatments. As in Artemia - fed treatments enriched with 5 and 10 mg of selenium nanoparticles (treatment 1 and 2) the lowest and in the treatment fed with Artemia - enriched 50 mg nanoparticles (Treatment 3) showed the highest levels of aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, creatinine phosphokinase and lactate dehydrogenase. The highest total protein content was observed in treatment 2, which was significantly different from other treatments (P <0.05). Overall, if the goal of using selenium-enriched Artemia in fish larval diet is to increase survival and growth rate and improve biochemical indices, the use of selenium nanoparticles of 5 and 10 mg/l is appropriate for enriching Artemia to feed fish larvae.