A numerical model analysis was performed to analyze the motion of a Korean designed automatic submersible fish cage system in waves and currents. The fish cage system consisted of a 12-angle rigid frame, net cage, cover net, 12 upper floats, 12 tanks (for fixed and variable ballast), mooring ropes, anchors, and control station. Simulations were performed with the cage at the surface of the water and at a depth of 20 m. Using a Morison equation type model, simulations of the system were conducted on the two configurations. The force parameters described both regular and random waves, with and without currents, and their values were considered as input to the model. Heave, surge and pitch dynamic calculations were made. Results were analyzed in both the time and frequency domains and where appropriate, linear transfer functions were calculated.