64 



WHOLESALE BREEDING 



one side for choice grades with good fin development, color, etc., and 

 the other for single-tails or fish with blemishes. 



As a final use for the water it can be placed to advantage as shown 

 in a large pond for the propagation of daphnia or other live food. The 

 fish pools should be drained in the winter in order to expose the bot- 

 toms to the action of frost, thereby killing lurking insect enemies. We 

 have shown an outlet on the daphnia pond, but ordinarily this is not 

 to be emptied. By draining it the stock of live food would not be 

 entirely lost, but many daphnia eggs would be carried away, and con- 



FiG. 52. Farm Breeding Ponds, Showing Detail of Sluice and Guard 



