Ciprofloxacin (CIP) and oxytetracycline (OTC) are commonly detected antibiotic species in breeding wastewater, and microalgae-based antibiotic treatment technology is an environmentally friendly and cost-effective method for its removal. This study evaluated the effects of CIP and OTC on Scenedesmus sp. in the breeding wastewater tailwater and the removal mechanisms of antibiotics. The results showed that Scenedesmus sp could increase antibiotic tolerance by enhancing antioxidant system activity. Compared to CIP, Scenedesmus sp showed better performance for OTC removal, the removal efficiencies were 100%, 96.87%, 95.75%, 90.18% and 83.91% at 0.1, 0.5, 1, 5, and 10 mg L