Animals use color in contexts ranging from mate choice to prey detection to mutualistic partner choice. Color perception is a function of the reflectance of a colour patch, the optical properties of the medium, the viewer’s visual system, and the ambient illumination spectrum. In aquatic environments, ambient illumination is dependent upon both depth and the optical properties of the water, both of which can be altered by anthropogenic processes. Many aquatic species have shifted deeper in response to warming surface waters (known as bathymetric shifts) at rates as high as 2 m/year, and dissolved and particulate compounds are increasing in many bodies of water. Changes in water color due to increased turbidity are well-described and can affect interactions mediated by color signals. Bathymetric shifts can result in similarly large changes to a species’ optical environment, but no studies have yet focused on how bathymetric shifts may impact visually-mediated interactions. Here, we draw attention to a potential link between changes in temperature and in an organism’s visual world. We synthesize information on color vision, optical environments in aquatic habitats, and signal coloration. We discuss (1) the conditions under which bathymetric shifts may impact color signaling; (2) what interactions might be affected by bathymetric shifts; and (3) how organisms might respond to these changes. As oceans warm, and temperature fluctuations grow more extreme, many species may be forced into deeper waters. Such shifts can affect an organism’s visual world, thus interfering with a variety of behavioral processes, with important consequences for fitness, population dynamics, and community structure.