Effect of salinity on the refractive index of water: considerations for archer fish aerial vision

The change in the refractive index between fresh and salt water was shown to cause a small shift in the apparent image location of an aerial object viewed from below the water's surface. The impact of this shift may be nominal with respect to archer fish Toxotes spp. spitting accuracy as its magnitude in the direction perpendicular to the spit is close to the width of the spit itself