Fishery resources are highly threatened by man-made chemicals that cause early life-stage mortality in fish, and could consequently block population recruitment. In a wide-scale and long-term investigation in Taihu Lake, we found that the temporal and spatial variation in embryonic mortality of crucian carp were consistent with the embryonic TDCIPP concentrations. We also confirmed in a well-controlled laboratory study that environmental concentrations of TDCIPP could cause embryonic mortality in crucian carp. Thus, TDCIPP was a major causal agent for mass embryonic mortality of crucian carp in Taihu Lake. These findings highlight the deleterious effect of this high-production-volume industrial chemical on global fishery and suggest ecosystem conservation should account for supervision of ubiquitous chemicals.