The retinal visual pigments of 52 species of deep-sea fish were measured by partial bleaching of detergent extracts. The retinae of 45 species contained only a single rhodopsin with maximum absorbance (Z(max)) at a wavelength between 474 and 490 nm, matching both the region of highest intensity downwelling sunlight and the maximum emission of most deep-sea bioluminescence. Seven species were shown to have more than one visual pigment within their retinae and these had Z(max) values that generally fell outside the usual range. One of these. Bonapartia pedaliota, was particularly interesting as, unlike most such multipigment species, it had one rhodopsin and one porphyropsin pigment, apparently based on different opsins. The relative proportions of the visual pigments in the seven multipigment species are presented.