We demonstrate fluidically tuned fluorescence enhancement on the colorimetric substrate with the plasmonic effects induced by the periodic gold nanocup arrays. The fluorescence enhancement by the plasmonic effect has been studied extensively by varying the geometries of nanostructures or the morphology of nanoparticles. In this study, however, the fluorescence enhancement without changing these parameters but simply by varying surrounding media on the colorimetric plasmonic surface is accomplished. The dynamic responses of fluorescence from self-assembled monolayer of dyes on the surface were monitored by flowing various fluids with different refractive indices. The dependence of the radiative decay rate as well as the scattering cross-section on the surrounding dielectric properties results into the selective enhancement of the fluorescence intensity, having a maximum at different surrounding refractive index for different fluorophores with different emission band centers.