Increasing the surface area of the plate heat exchangers (PHEs) has recently been one of the focuses of the industry. Improved surface shapes provide greater heat transfer and also become an important key point in energy saving. In this study, a fish-gill pattern is modeled on the plate surface and a thermo-hydraulic evaluation is performed on it. It is known that living respiratory organs such as fish gills are the natural heat exchangers that provide the best heat and mass transfer. Thus, the focus is on both increasing the compactness and heat transfer and reducing the pressure drop for PHEs. Comparative simulation studies are conducted between the fish-gill patterned PHE and the commercial Chevron PHE for water fluid. The study results show that the heat transfer rate of the fish gill patterned PHE is 15% higher compared to the Chevron PHE while the pressure drop is close. The compactness and efficiency values are also higher than those of the Chevron PHE. It is observed that the pressure consumption is higher because the surface geometry is complex, and the channels are narrow. Therefore, this study can be considered as a guide for the realization of PHE surface shape designs.