Abstract:The steady-state level of the P450arom (P450aromA and P450aromB) mRNAs of male Pelteobagrus fulvidraco cultured at different temperatures and growth conditions were analyzed by RT-PCR, and GSI, HSI, CF, serum sexual steroid hormones testosterone (T) and estradiol (E2) levels were measured by 125I radioimmunoassay (RIA). The spatial expression result showed that P450aromA mRNA was not present in ten tissues of male P. fulvidraco, including spermary, liver, stomach, intestines, gill, heart, spleen, kidney, head kidney, and brain. P450aromB was expressed in brain and intestines. Expression of P450aroms was fist linked to temperature, serum sexual steroid hormones testosterone (T) and estradiol (E2) level. The changes in mRNA level of P450arom shared the same trends with serum E2 and T cultured at different temperatures. Our results suggested that P450aromA may be related with spermatogenesis. The high expression level in the brain of the male fish may be directly involved in the maintaining of sperm vitality and spermiation process. The results showed that higher temperature made more significant effects on sperm vitality and spermiation process.