BROOK TROUT 



supplied daily with worms, another with live minnows, 

 and the third with those small dark-colored water-flies 

 which are to be found moving about on the surface 

 under banks and sheltered places. The trout fed 

 with worms grew slowly, and had a lean appearance ; 

 those nourished on minnows — which it was observed, 

 they darted at with great voracity — became much 

 larger ; while such as were fattened upon flies only, 

 attained in a short time prodigious dimensions, weigh- 

 ing twice as much as both the others together, although 

 the quantity of food swallowed by them was in no- 

 wise so great. 



Lanman has stated that one principal cause of the 

 great variety in color of the brook trout is the differ- 

 ence of food ; such as live upon fresh-water shrimps 

 and other Crustacea are the brightest; those which 

 feed upon May-flies and other aquatic insects are the 

 next; and those which feed upon worms are the dull- 

 est of all. Trout which feed much upon larvae {Phry- 

 ganidd) and their cases are not only red in flesh but 

 they become golden in hue and the red spots increase 

 in number. 



Professor Agassiz has said " the most beautiful trout 

 are found in waters which abound in Crustacea ; direct 

 experiments having shown that the intensity of the 

 red colors of their flesh depends upon the quantity of 

 Gammarida. (fresh-water shrimps) which they have 

 devoured." 



Mr. Cheney once wrote that " fishes are probably 



38 



