An improved Coanda effect fish pump that allows for improved pump performance with enhanced and unsymmetrical-irregularities features in circumferential flow gaps and orifice flutes that improve water flow distribution and pump performance. Design features improve fish quality during pumping and can be designed to remove sea lice from salmon. The features reduce spinning in the pump, correct for unsymmetrical input water pressure distribution, and reshape water velocities to more effectively remove sea lice.