036 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [170] 



l)ike, trout, and all those fish of which only a small number is kr\)t are 

 put in small tanks. 



If (luring severe winter weather the ice in the tanks gets very thick, 

 it must be removed so that the tish cannot hurt themselves by knocking 

 against it. On small pond farms which have only a few small tanks, it 

 will be well to prevent entirely the formation of ice by covering the-n 

 in very severe cold weather with poles, over which is spread a thick 

 layer of straw ; on days when there is no frost this covering is taken oflt" 

 and again put on in the evening. If snow falls, it must be removed 

 every day, so that the air has free access to the tank at all times. In 

 A'cry cold weather water should be poured into the tanks from time to 

 tinie, especially when the influx and outflow are not regular. 



In Jish-houses. — Von Reider* gives the following directions for erecting 

 flsh-houses over brooks and ponds, which in medium-sized and small 

 pond farms may prove useful: " Fish-houses are the most suitable re- 

 ceptacles for fish. They consist of large and small buildings according 

 to the extent of the fisheries which they are to serve. They are ])laced 

 over brooks or ponds which have a strong steady current. All kinds 

 of receptacles for fish are benefited by being placed in swift-flowing 

 water, or in ponds where many springs keep the water always at an 

 even depth. Fish-houses may be of different size and shape, but they 

 should never have more than one story. Their size will depend princi- 

 ])ally on the internal arrangements. The walls may be entirely of stone, 

 or better still of framework filled in with clay. The walls of many fish- 

 houses are composed of simple boards. Stone walls, of course, aflbrd 

 greater security; but boards keep the house warmer. The low roof is 

 covered Avith reeds or straw , but in such a manner as to admit the air, 

 which is very beneficial for the fish during their long imprisonment. Ac- 

 cording to the size of the house and the quantity of water, it contains 

 either one or several fish-tanks. The houses should, if possible, re^t on 

 ]>illars or ])osts in the water, so that air and water may enter the different 

 tanks sinuiltaneously, at least on three sides. The separations of the 

 different tanks or compartments, which have to be in the water, are 

 made either of laths or boards, through which holes have been bored 

 at certain intervals, l^aths are preferable for this purpose, and may 

 be intertwined with willow branches. Nets may also be emi)loyed for 

 this purpose (I, for my part, would not recommend these, as they soon 

 rot when left in the water for any length of time). At the bottom these 

 tanks must be fastened to the depth of about 60 centimeters, between 

 two beams. To secure them still more they are inclosed by strong poles 

 ])laced at intervals of 60 centimeters, which rise 60 to 90 centimeters 

 above the surface of the water, so that ice and drift-wood may not do dam- 

 age to the inclosure of laths. It is very advantageous if the water can 

 fall into the tanks from some height. The water in the different compart- 

 ments should always be deep enough to prevent its freezing in winter. 



* Vou Reider, Do* Game der Fischerei, 1825. 



