Fishes . s shadow overthe paler lower parts. In shallow waters or in rivers the bottom is not uniformlycolored. The fish, especially if it be one which swims closeto the bottom, is better protected if the olivaceous surface ismarked by darker cross streaks and blotches. These give thefish a color resemblance to the weeds about it or to the sandand stones on which it lies. As a rule, no fish which lies onthe bottom is ever quite uniformly colored. In the open seas, where the water seems very blue, blue 7Q 8o The Colors of Fishes colors, and especially metallic shades, take the place of oliva-ce
Fishes . s shadow overthe paler lower parts. In shallow waters or in rivers the bottom is not uniformlycolored. The fish, especially if it be one which swims closeto the bottom, is better protected if the olivaceous surface ismarked by darker cross streaks and blotches. These give thefish a color resemblance to the weeds about it or to the sandand stones on which it lies. As a rule, no fish which lies onthe bottom is ever quite uniformly colored. In the open seas, where the water seems very blue, blue 7Q 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, especiallyin the warm seas, red pigment takes the place of olive. At amoderate depth a large percentage of the fishes are of vari-ous shades of red. Several of the large groupers of theWest Indies are represented by two color forms, a shoreform in which the prevailing shade is olive-green, and adeeper-water form which is crimson. In several cases an inter-. FiG. 03.—Garibaldi (scarlet in color), Hi/p-inpops rubicunda (Girard). La JoUa, San Diego, California. mediate-color form also exists which is lemon-yellow. Onthe coast of California is a band-shaped blenny {Apodichthysflavidus) which appears in three colors, according to its sur-roundings, blood-red, grass-green, and olive-yellow. The redcoloration is also essentially protective, for the region inhab-ited by such forms is the zone of the rose-red alga:;. In thearctic waters, and in lakes where rose-red algae are not found,the red-ground coloration is almost unknown, although redmay appear in markings or in nuptial colors. It is possiblethat the red, both of fishes and alga;, in deeper water is relatedto the effect of water on the waves of light, but whether thisshould make fishes red or violet has never been clearly under-
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