This study was to survey proper condition of nitrate removal by hydraulic retention time (HRT) and measured growth of black rockfish (Sebastes schlegeli) and giant croaker (Nibea japonica) in the seawater recirculating culture system designed for nitrate removal. Nitrate conversion to nitrogen at 8 hr-HRT was higher than 16 hr-HRT, amounting to $32.2;g/m^3/day$ in the seawater recirculating culture system. The removal efficiency of nitrate improved when dissolved oxygen was situated less than 0.5 mg/L. Daily growth rate (DGR) and feed efficiency (FE) of S. schlegeli with mean body weight of 108 g in 8 hr-HRT were significantly higher values than those in 4 hr-HRT (P<0.05). The DGR and FE of N. japonica with mean body weight of 12 g in added carbon system showed not differing in the values from N. japonica in control system (P>0.05).