8o The Colors of Fishes 
colors, and especially metallic shades, take the place of oliva- 
ceous gray or green. As we descend into deep water, especially 
in the warm seas, red pigment takes the place of olive. Ata 
moderate depth a large percentage of the fishes are of vari- 
ous shades of red. Several of the large groupers of the 
West Indies are represented by two color forms, a shore 
form in which the prevailing shade is olive-green, and a 
deeper-water form which is crimson. In several cases an inter- 
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Fie. 68.—Garibaldi (scarlet in color), Hypsypops rubicunda (Girard). La Jolla, 
San Diego, California. 
mediate-color form also exists which is lemon-yellow. On 
the coast of California is a band-shaped blenny (A podichthys 
flavidus) which appears in three colors, according to its sur- 
roundings, blood-red, grass-green, and olive-yellow. The red 
coloration is also essentially protective, for the region inhab- 
ited by such forms is the zone of the rose-red alge. In the 
arctic waters, and in lakes where rose-red alge are not found, 
the red-ground coloration is almost unknown, although red 
may appear in markings or in nuptial colors. It is possible 
that the red, both of fishes and alge, in deeper water is related 
to the effect of water on the waves of light, but whether this 
should make fishes red or violet has never been clearly under- 
