The given value of the daily food weight is naturally of only approximate size. The 

 daily food weight is largely dependent on the temperature, the size of fishes to be fed, 

 and the kind of food, 



TlThen feeding with fish food, flngerlings of rainbow trout, at different temperatures 

 require about the following rations: 



at 5 degrees centigrade about 2 ii of their weight. 



at 7 to 10 degrees centigrade " 3 !? to 5^ of their weight.- 



at 10 to 15 degrees centigrade " 5 ^ to 7 ){ of their weight, 



at 15 to 18 degrees centigrade " 7 ^ to 8 " of their weight. 



According to Cornelius, rainbow trout reach the maximum of their food requirements 

 at a ten^jerature of 19 degrees centigrade. 



For rainbow trout broodlings under 0,5 gram weight, Cornelius calculated their food 

 requirements as follows: 



At a temperature of 13 degrees, when feeding spleen ... 16 ^ of their weight. 

 At a temperature of 13 degrees, when feeding daphnae .. 22 ^ of their weight. 

 At a temperature of 17 degrees, when feeding daphnae ., 38 ^ of their weight. 



It follows that the smaller the trout (to be fed) are, the greater must be the 

 daily weight of food measured out . 



With regard to the kind of food, Cornelius found that fingerlings of rainbow trout 

 require the following rations: 



At a temperature of 10 degrees centigrade, feeding upon whiting 



L,2 % of their own weight. 

 At a temperature of 1^.1 degrees centigrade, feeding upon spleen 



10 % of their own weight. 

 At a temperature of 9.2 degrees centigrade, feeding upon Gammarus 



3.7 % of their own weight. 

 At a temperature of 9.3 degrees centigrade, feeding upon Ghironomus 



7.4 % of their own weight. 



The total amount of food for a pond within a definite time period is to be calculated 

 similarly as with carps by multiplication of the estimated total increase in this time, 

 by the food quotient of the food given. The distribution of the total amount of food 

 during individual months in the normal growing of one year fingerllngs into table trout, 

 is somewhat as follows: 



March 1^ June 15^ September 17^ 



April U% July lt% October 1A% 



May 1% August 18jt November 10^ 



It must be remembered that the temperature differences in the trout paid in the 

 course of the year are not so great as a rule as they are in the carp pond and that the 

 "daily food weights" diminish somewhat with the growing up. 



During the first few weeks, trout broodlings should be fed four times dally, at least. 

 Older trout are fed from 2 to 4 times daily, according to the amount of food given at each 

 feeding. During the cold season, it is at times sufficient to feed Just once per day, or 

 feedint^ may be temporarily suspended. In contrast to carps, a not inconsiderable growth 

 Increase can also be achieved with trout in the winter. 



In case of digestive disorders or excessive losses, feeding has to be stopped immedi- 

 ately for a week, or even for from 2 to 3 weeks. Variety in the food shows good results. 

 Sudden chsinges in the diet are to be strictly avoided. If such changes become nece sary, 

 the fish are to be accustomed to it gradually. 



148 



