FISHES 141 



all fishes are darker above than below, many of them 

 being pale underneath. 



The most brilliantly colored fishes are found in 

 the tropical seas and principally among the in- 

 habitants of coral reefs. Many fishes bear protective 

 colors, as is shown by the fact that individual fish 

 of the same species vary in color according to the 

 surroundings in which they are taken. In other 

 words, fishes like the chameleons change their color 

 more or less to correspond to the background upon 

 which they dwell. 



Color changes are much more highly developed 

 in some species than in others. Perhaps the most 

 striking example of color adaptation among the 

 fishes occurs in the flounders. It has been shown ex- 

 perimentally that the southern flounder, if placed 

 on backgrounds of various shades and patterns, 

 simulates them to a surprising degree ; that is, when 

 placed on red, it turns red, on yellow it turns yel- 

 low, and so on, making it possible to produce in this 

 fish any color desired. Furthermore when it is placed 

 on» fine sand it not only acquires the color of the 

 sand but the markings on the body become small; 

 when placed on coarse shells the markings become 

 larger, showing that both the color and the pattern 

 are simulated. 



Foods 



Fish eat a very large variety of foods, including 

 many plants and practically all aquatic animals of 

 suitable size. The majority of the species subsist on 

 an animal diet and are said to be carnivorous. Those 



