Effects of green wavelength light on antioxidant and non-specific immune responses of the olive flounder Paralichthys olivaceus maintained at different stocking densities

•We examined the effects of green light on antioxidant and non-specific immune responses in the olive flounder at various stocking densities.•Green light reduced the negative effects of high stocking density on survival.•Antioxidant enzyme was lower and immunity was higher at high stocking densities in fish reared under green-light conditions than white light.•DNA damage, which is higher at higher stocking densities, was reduced under green-light rearing conditions.•Green light has positive effects in olive flounder and thus represents a strategy for use of high stocking densities in aquaculture.