The role of Psudoalteromonas piscicida biofilm structures on the corrosion behavior of carbon steel was studied under two different hydrodynamic conditions, namely, orbital shaking incubator and flat plate bioreactor. Results showed a high number of wide and deep cracks on the metal surfaces exposed to flat plate bioreactor. On the contrary, the corrosion rate of carbon steel decreased and reached to its lowest value after two weeks of inoculation under orbital shaking condition. Different biofilm structures in both hydrodynamic conditions were observed through surface analysis. Adding farnesol as biofilm inhibitor exhibited different effect on the hydrodynamic conditions on biofilm structure.