156 FISH HATCHING. 



fish near him, and flies at and bites them 

 when he sees them coming ; he does not 

 even spare the young grayling that escape 

 from the tank above. These he will " carry 

 about in his mouth like a cat does a 

 mouse." 



The young salmon and trout certainly 

 eat the young grayhng when they can 

 catch them, for they are very active ; 

 they also eat young perch. I have placed 

 perch spawn in their tanks, and as the 

 perch, which are exceedingly minute, hatch 

 out, they are caught up and devoured in an 

 instant, 



TUENING OUT FISH. 



A great question now arises as to turning 

 out the fish into the streams, i.e., at what 



