Rod and cone visual pigments in the goldfish

This microspectrophotometric (MSP) study has confirmed that goldfish, acclimated under a certain light and temperature regimen, possess mixtures of porphyropsin and rhodopsin in their rod outer segments. Moreover, the MSP spectra from the red, green and blue cones of these acclimated goldfish also shifted to shorter wavelengths from spectra of pure 3-dehydroretinal based visual pigments. Thus, goldfish retinas may possess a total of eight visual pigments (two rod pigments and six cone pigments) instead of four (one rod pigment and three cone pigments). Possibly, a common control mechanism, governed by external conditions, regulates the utilization of retinal and 3-dehydroretinal for the biosynthesis and/or regeneration of visual pigments in both rods and cones.