The feasibility of foam separation to remove protein in aquacultural recirculating water was investigated. From the results of batch foam separation on protein removal, superficial air velocity and initial protein concentration in bulk solution were found to be important operational factors in determining removal rates of protein. The protein removal rate by batch foam separation was proportionally increased with the superficial air velocity. Performance characteristics of continous foam separator were highly dependent upon the operating parameters of superficial air velocity, hydraulic retention time(HR) and foam height. Removal efficiency of protein increases with increasing superficial air velocity and HRT, and independent on foam height. As DO concentration was increased with superficial air velocity, foam separator is also used for oxygen addition. It could be confirmed that foam separator might offer better perspective for protein removal in aquacultural recirculating water