[11] POND CULTURE. 4^7 



cally cold, and not well adapted to fish-culture. Fish of prey, especially 

 trour, which live on their fellow-beings, will flourish in such water If 

 a pond fed by spring water exclusively has a sandv bottom, it must be 

 classed among the so-called poor ponds ; if such water coutaiuN a consid- 

 erable quantity of animal refuse, it is hurtful to the fish and should be 

 allowed to flow off. A pond containing such water can onlv be used for 

 fish-culture if other and healthier water is introduced. 



" h. Snow and ram icater contains nutritive matter in a diluted form 

 fills the ponds evenly, and is beneficial to the fish during the rainy sea- 

 sons and thunder-storms which occur during summer. Eain-water in- 

 variably contains a good deal of fresh nourishing matter. 



"c. Brooh and river icater is more or less soft or hard, accordino' to 

 the influence which the heat of the sun has upon it and the quantity of 

 loreign matter which it carries along with it. Ponds are generally sup- 

 plied by this water which, on the whole, is favorable to fish-culture. 



"^. Peat, marsh, or forest icater is usually pure, of a dark color, and 

 marshy flavor. It contains but little fish-food, and becomes suitable 

 for fish only after having been in the ponds for some time, exposed to 

 : the influence of the atmosphere and mixed with snow, rain, and other 

 water. If such water flows into the ponds from peat-bogs and marshes, 

 ; the ponds will be poor, and can only be improved by being drained fre- 

 I quently and by introducing rain-water from the nearest fields. 

 , " e. Pond icater is suitable, as a general rule. It is warmer than river 

 ; or spring water, and is specially adapted to the supply of winter ponds 

 , and tanks. The water of good ponds, or of ponds which at certain 

 , periods are used for agricultural purposes, contains dissolved sub- 

 1 stances and is wholesome for fish. Muddy water coming from culti- 

 i vated fields carries much humus and nutritive matter. If the water of 

 , a pond when agitated by wind- remains colorless and clear, this is an 

 , indication that the soil is poor, while a brownish-yellow water indicates 

 i a rich bottom. Water from peat-bogs or from iron mines, or water 

 : which IS saturated with manure or particles of lime, is hurtful to the 

 I fish, and unless a sufBcient quantity of pure water is introduced the 

 I fish will grow sick or die out. Reddish water, having an oily surface, 

 I contains too much iron, tannin, and gallic acid, and is, therefore, in- 

 ! jurious to fish. Water which, during the rainy seasons, flows into the 

 ^ ponds from cities and villages contains much new and rich food-matter, 

 I and should, therefore, be employed whenever practicable, of course pre! 

 I venting any large quantity of manure water from mingling with it. 

 I Water from chemical factories is. generally hurtful to fish."* 

 I 5. The quality op the soil— The bottom of the pond should re- 

 ^ tain the water and be well supplied with fish-food. The main source 

 I offish-food will alv^-ays be the bottom of the pond, for it is not certain 

 I that the water flowing into the pond will contain a sufficient quantity 

 ^ of^ food. Sandy loam soil or loamy sand soil will contain most food. 



* Horak, Teichwirthschaft, 1869. 



