192 FISH CULTURE. 



in order to allow the soil to exhale and purify, and 

 the weeds to die down. Some weeds are indispen- 

 sable, as they harbour food, serve to aerate and keep 

 pure the water, and are needed for the fish to spawn 

 amongst. Indeed, the fish cannot spawn without 

 them ; and, added to this, the spawn is said to re- 

 quire the aeration afforded by the weeds for its proper 

 vivification. The little gold fish often die off in 

 great numbers, from no other cause than that of 

 being placed in tanks or reservoirs where there are 

 no weeds for it to rub itself against, in order to free 

 itself from the spawn. The Water Crowsfoot is one 

 of the most useful weeds for ponds, but the Anacharis 

 Alsinastrum, or American weed, as it is commonly 

 termed, should be avoided, or it will soon choke up 

 the pond. 



Ponds should be fished once in every three or four 

 years ; they do not pay if left for longer intervals. 

 A few pairs of the larger fish should be left as 

 breeders, with whatever fry may exist ; but the 

 middle-sized fish should be taken out — that is, the 

 fish from two to four or five pounds. Carp, for 

 example, grow slowly up to about three-quarters of 

 a pound weight, when they seem to strike out and 

 grow very rapidly up to five or six pounds, if food be 

 plentiful and the water of good temperature. From 



