The present study aimed to investigate the protective effect of Azolla pinnata 10 % dietary supplementation against Abamectin at sublethal concentration in Nile Tilapia. After calculating the toxicity of abamectin in a bioassay experiment, the value of 96h-LC50 was 0.055 mgL-1 then. Four groups estimated to study the effect of Azolla dietary supplementation, the control group, was fed a basal diet, Azolla group was fed on a prepared diet of Azolla 10 % , the ABM group treated with one-tenth 96h-LC50 of Abamectin was fed a basal diet the fourth group was ABM-Azolla, treated with one-tenth 96h-LC50 of Abamectin and fed on a prepared diet of Azolla 10 %. The experiment extended to 28 days. No dead fish observed. Biochemical changes including oxidative stress indices were assessed. The results showed elevation in the levels of serum alanine and aspartate aminotransferases (ALT and AST), urea, creatinine, and malondialdehyde (MDA), meanwhile, the antioxidant enzyme activity (CAT) and reduced glutathione (GSH) content were markedly declined in the ABM –exposed group. Interestingly, Azolla supplementation diminished these variables with improving liver and kidney markers. Consequently, Azolla pinnata may be considered a potential natural antioxidant for the alleviation of Abamectin toxicity in Nile tilapia.