224 DOMESTICATED TROUT. 



guish it from all other trout. A mullet caught in a 

 lake looks like all the other mullets of the lake, so 

 with the white-fish and others ; but each trout has its 

 individual marks which distinguish it from all others. 

 The trout also of different brooks and lakes all differ 

 from one another, so that the streams in which they 

 are caught can frequently be told by the looks of the 

 fish. Their different localities in the same stream also 

 affect their appearance. Over a light gravelly bot- 

 tom the trout grow light-complexioned, and they vary 

 through all shades of complexion, from this to the 

 dark slimy trout, almost as black as a bull-head, which 

 is caught in shady places over black, muddy bottoms. 

 And what is still more remarkable, trout have the 

 chameleon gift of almost instantly changing their tint 

 within certain limits.* 



They do not, strictly speaking, change their color, 

 because a black trout will remain a black trout and a 

 silvery trout will remain a silvery trout wherever you 

 expose them; but a complete change comes over 

 their whole complexion, so to speak, as if the light to 

 which they are subjected were diffused through them, 

 so that, in passing from a dark, muddy bed over light 

 gravel, they will in less than a minute take the general 

 hue of the gravel, and vice versa in passing from 

 gravel to mud.f 



The natural food of trout is very various. They 

 are carnivorous from choice, though omnivorous in 



* The black bas* and some other fish have the same power 

 to some extent. 



t This change takes place, not in the scales, but in the skin 

 underlying the scales. 



