HAACK RAISING SALMONOIDS IN INCLOSED WATERS. 683 



Young saibling, as well as young trout, unless placed in large artifi- 

 cial brooks, should at first be fed exclusively on small crustaceans. 

 Although it may in some localities involve trouble and expense to pro- 

 cure such living food, it is everywhere possible to obtain it. As soon as 

 the young fish have grown a little larger the larvse of various kinds of 

 gnats, which surely can be obtained everywhere, are a most suitable 

 food. Only after the young fish have for several weeks been exclu- 

 sively fed on live food, artificial food should be given to them. The best 

 food for all young salmonoids will under all circumstances be the brain 

 of cattle, ground fine. With a sharp brush the brain is rubbed two or 

 three times through a close wire-sieve, and this sieve is then washed out 

 in the artificial brook close to the entrance. In the beginning but very 

 little should be given, and all the remains should be carefully removed; 

 gradually, however, the quantity should be increased. As soon as the 

 fish are a few months old the feeding process will gradually become 

 easier, and the brain should then be rubbed through a coarse sieve. 

 But rarely will any particle of the brain fall to the bottom, as the fish 

 will greedily devour it all. At this period it will be well to vary the 

 food a little ; and I can conscientiously recommend raw meat of the 

 muscle part, for the smaller fish, of course chopped fine. Wherever 

 there are properly inspected horse slaughter-houses horseflesh may be 

 used, which is of course cheaper ; but wherever you are not absolutely 

 certain of obtaining healthy flesh, the more expensive beef should be 

 used. The little trouble and expense should not prevent any one from 

 giving the young fish from time to time worms chopped fine, as well as 

 the larvae of the phryganids carefully removed from their shell, which 

 are found in great abundance in every water. The small expense in- 

 curred by thus varying the food will be amply repaid by the better con- 

 dition of the fish. 



The chief point in feeding fish in inclosed waters will be to observe 

 the greatest cleanliness ; and the basins should every day be carefully 

 cleaned of all remnants of food and excrements. It will, therefore, be 

 found advantageous to place the young fish in elevated basins, so that 

 all remains of food &c, can be removed by means of a gutta-percha 

 tube. 



As long as the fish are quite small such a tube should be furnished 

 with a fine sieve. If the basins are not elevated the cleaning must be 

 done by means of a pipette. 



The most scrupulous care in removing all remnants of food and dirt 

 from inclosed waters is absolutely required for raising salmonoids. In 

 natural brooks, which have an abundance of aquatic plants, the numer- 

 ous small crustaceans keep the water sufficiently clean, while in artificial 

 brooks man must be the scavenger. 



During the first year no food can be too expensive, as the quantity of 

 food required is not very great. I have kept an exact account, and even 

 when using brain, which is the most expensive food, from spring till 



