226 FISH CULTURE 



built across a stream of water, provided the 

 latter is of moderate size, and is not subjected 

 to any floods; but if the pond is so con- 

 structed the upper end must be carefully 

 screened to prevent escape of the captives. 



As frogs subsist entirely upon living crea- 

 tures, and will devour nothing dead, all ponds 

 excepting those designed exclusively for tad- 

 poles, must contain an abundance of water- 

 grasses and flowering aquatic plants. Pond- 

 lilies are particularly effective. It is also de- 

 sirable that flowering plants which thrive in 

 wet places be maintained on the strips of 

 ground around the ponds, as flowers and 

 grasses attract insects and other small forms 

 of life upon which frogs feed. 



Each pond for hatching eggs and caring for 

 tadpoles of the leopard species, should be at 

 least 60 feet long and 20 feet wide. There is 

 no necessity for it to be surrounded by a patch 

 of grassy ground, nor to contain lilies and 

 other flowering plants, because tadpoles will 

 readily feed on dead fish and liver. Almost 

 any kind of bottom will answer for tadpoles of 

 the leopard frog. As this species is of little 



