Abstract: The toxicity of Cu2+ to fish during early developmental stages was reviewed. To fish embryos, Cu2+ with a high concentration may reduce hatching rate and increase malformation rate, leading lethal toxicity to fish larvae and juveniles as well. Thus, the effects of median lethal concentration and safe concentration of Cu2+ to fish larvae and juveniles were analyzed. Combined toxicity between Cu2+ and other heavy metals or poisons was also discussed. Based on the review, recommendations to quality monitoring of fishery water and usage of fisheries drugs were suggested.