Water pollution of heavy metals such as cadmium is a serious problem in China. Cadmium is toxic to cellular processes such as the transport and metabolism of iron. The nucleotide sequences of serum transferring (c-sTf) and hepcidin (c-Hep) genes from croceine croaker (Pseudosciaena crocea) were determined. The full-length cDNAs of c-sTf and c-Hep were 2,486 and 850 nt, respectively. After cadmium exposure (CdE), fish serum iron increased significantly and reached a high level at 24 h, after which it decreased and reached normal levels after 72 h. TIBC increased to a high level at 24 h and maintained that to the end of the experiment. Tf saturation increased to a high level at 24 h, then decreased and returned to normal after 72 h. Higher erythrocyte numbers in the blood were found after 24 h. c-sTf mRNA in fish liver significantly increased at 24 h and maintained to the end of the experiment. c-Hep mRNA expression significantly increased at 24 h and reached a high level at 48 h, then decreased to normal by 72 h. Therefore, it suggests that iron status was the signal for mRNA expression of hepcidin in liver, while erythrocytes changes in blood were the signals for that of sTf.