REARING THE YOUNG FRY. 169 



place the spout, and cut off the whole supply of water 

 from the fish below. 



I recall now several instances in which most disas- 

 trous results have been so caused. This point is the 

 more important, because the consequences of neglect 

 are so very fatal ; in the hot weather, when the young 

 fry are being raised, two hours without change of water 

 being often sufficient to kill a whole box or pond full. 



They should be kept where new, unused water will 

 run over them. This is very important. At first, 

 when they begin to feed, the effete matter coming 

 from them is very slight in quantity, and harmless ; but 

 it rapidly increases with the growth of the fish, and 

 becomes a prolific source of impurity and disease, as 

 can be easily comprehended when it is considered 

 what the amount must be from one thousand to ten 

 thousand fish feeding almost hourly. 



The water, therefore, that is used for the nursery, 

 should be fresh from the spring or brook, and should 

 not be that which has run over other trout above, un 

 less the stream has run far enough to purify itself. 



The place in which they are kept should be well 

 shaded. Sunlight fosters the growth of fungi and con- 

 fervas, and predisposes the young fish to some of the 

 diseases to which they are subject ; and when disease 

 breaks out it makes bad matters worse. The young 

 fry should be therefore guarded against it, as well as 

 the eggs. Shade never killed a trout yet, young or 

 old. Sunlight has killed a great many. It cannot be 

 denied that trout often come out voluntarily into the 

 sun, but they should nevertheless always be placed so 

 8 



