Enables G protein-coupled photoreceptor activity. Involved in several processes, including hyaloid vascular plexus regression; optokinetic behavior; and phototransduction. Acts upstream of or within several processes, including detection of temperature stimulus involved in thermoception; entrainment of circadian clock by photoperiod; and thermotaxis. Located in sperm head plasma membrane. Is expressed in eye and future brain. Orthologous to human OPN4 (opsin 4). [provided by Alliance of Genome Resources, Apr 2022]