The dietary impacts of water-soluble (vitamin C) and fat-soluble (oregano essential oil, OEO) antioxidants on the stress responses and redox status of Astyanax aff. bimaculatus exposed to the air were assessed. Five diets with vitamin C (VC 0, VC 40, VC 80, VC 120, and VC 160 mg kg − 1 ) with or without OEO inclusion (0 or 1,000 mg kg − 1 ) were evaluated. After 55 days of feeding, sh were exposed to air for 5 min. VC 120 and VC 160 reduced glycemia. In the gills, VC 120 and VC 160 reduced oxidative damage (malondialdehyde, MDA, and carbonylated proteins, PC) and superoxide dismutase (SOD) activity only in the presence of OEO. By contrast, in the absence of VC, OEO increased PC levels and SOD activity. In the liver, all VC concentrations, without OEO, reduced MDA, whereas, in the presence of OEO, vitamin C reduced MDA only at VC 40 e VC 160. All vitamin C concentrations, independently of OEO, reduced PC levels and SOD and catalase (CAT) activity. By contrast, OEO increased CAT and glutathione S-transferase (GST) activity regardless of VC level. Although VC 40 with 1,000 mg kg − 1 OEO was su cient to reduce oxidative damage to lipids in the gills and liver, reduction in protein and lipid damage in the gills was only obtained with at least VC 120 + OEO. Therefore, we recommend simultaneous supplementation of these antioxidants, as their combined use is more e cient in reducing oxidative damage in A. aff. bimaculatus subjected to air.