Abstract: To investigate the effects of dietary selenium (Se) levels on growth performance, antioxidant capacity, and Se-enriched production in Asian swamp eel (Monopterus albus), an 8-week feeding trial was conducted with six experimental groups four replicates each, 35 eels per replicate; initial body weight: (7.71±0.01) g. Five Se-supplemented diets (measured Se levels: 1.39, 1.85, 2.91, 4.59, and 9.08 mg/kg) were formulated by using selenium yeast (2000 mg/kg Se) added to a basal diet (control, 0.92 mg/kg Se). Results showed that: (1) No significant differences in survival rate, weight gain rate, specific growth rate, or feed conversion ratio among groups (P>0.05); (2) Serum glutathione peroxidase (GSH-Px) activity in 1.85—9.08 mg/kg groups, serum total superoxide dismutase (T-SOD) and catalase (CAT) activities in 1.85 mg/kg group, and total antioxidant capacity (T-AOC) in 4.59 mg/kg group were significantly higher than that in the control. The selenium accumulation in tissues followed the order: liver>skin>kidney>spleen>muscle>intestine. M. albus showed good tolerance to dietary selenium yeast, with Se levels ≤9.08 mg/kg having no impact on growth. Optimal Se supplementation (2.68—2.93 mg/kg) enhanced antioxidant capacity in juvenile eels (7.71 g). Elevated dietary Se promoted muscle Se deposition, supporting Se-enriched production, though excessive Se may inhibit antioxidant function.