fluviatilis (6). In diurnal fish, vision is the
main sensory modality (4) and cone cells
have been reported to be present (1,2), thus
supporting an evolutionary significance for
color discrimination in fish. Since in natural
habitats environmental color is a characteristic
which varies according to place, and
may even change over time in the same
habitat, the effect of color on the fishs life is
expected to be associated with the predominant
habitat color. According to Levine and
MacNichol Jr. (1), the visual environments
of fish are blue, green or near infrared, although
the other studies cited above have
shown mainly the two former colors as significant
to the fish. Therefore, color effects
on a fishs life seem to be a species-dependent
phenomenon which may be related to
specific habitat characteristics