BREEDING NATURAL FOOD ARTIFICIALLY FOR YOUNG FISH. 279 



of Mr. Von Scheidlin will probably be made known by the Commission. In the mean- 

 time, I quote from the letters already received : 



The entire question of the food of fish rests upon two important points: (1) Upon the recognition 

 of the fact that their food consists of insects, infusoria, Crustacea, worms, amphibia, and fish, in 

 their various stages of transformation; and (2) upon the observation of the fact in nature that the 

 females of insects, amphibia and fish deposit their spawn only in those places in which are found 

 suitable conditions for the future survival of the young; and if the pisciculturist produces these con- 

 ditions according to the needs of the animals, he can induce them|to deposit their brood in definite 

 places, and can produce the food for the fish wherever he likes, and in greater quantities than are 

 produced in the waters by natural processes. Fish food should be living and consist of bits or pieces 

 as large as the mouth-opening of the fish to be fed. 



The principle of rational feeding according to Justus von Liebig, Boussingault, and Gronven, 

 is briefly this: The chemical composition of the food should conform to the chemical composition of 

 the body of the animal to be fed — that is to say, in the case of fishes, being cold-blooded animals, 

 they must receive food that in turn consists of cold-blooded animals — a principle that runs through 

 all nature. For example, you can raise maggots easier, quicker, and in greater quantities upon the 

 flesh of amphibia and fish, than upon that of mammals. * * One kilogram of food composed of 



insects, amphibia, or fish, is equal in quantity to 16 to 18 kilograms of the flesh of mammals. 



By means of natural food the fish fry grow seven times faster than by the food of mammal flesh. 

 * * * Since May of last year [the letter is dated in August, 1893] I have been feeding carp fry 

 with artificially -reared natural food, and the fish which when put into the pond were If centimeters 

 long (10,000 of them to 114 acres of water surface) are to-day 16 to 18 centimeters long. Those that 

 were 18 decigrams in weight are now 3^r kilograms, and those that were 5 decigrams are now 1 to If 

 kilograms. * * Of all these natural foodstuffs, 2f to 3 kilograms produce the same increase in 



the fish fed as 14 to 20 kilograms of the flesh of mammals, and it is produced three-fourths cheaper 

 with the natural food. * Two years ago I produced within 100 days by means of natural 



food, from carp fry If centimeters long, carp of If kilograms in weight. 



At the risk of repeating a portion of the substance of what has already been 

 quoted from these papers, I will give one more extract : 



Not till now do I see from your letters that you lay the greatest stress upon the culture of young 

 fish up to the first or second year ; and that is the correct idea and the one I hold to myself. The food 

 of the brood after the loss of the umbilical sac must be living, not finely-chopped mammal flesh, because 

 while the fish upon the latter diet may become large they will not become strong. If you can not give 

 them living food give them, at any rate, finely-chopped fiberless amphibia or fish flesh, as this is 50 

 per cent better than mammal flesh, while living food, on the other hand, is 1,000 per cent better. 



The production of living food for brood and young fish is the easiest and cheapest, and this food 

 can be fed until the fish have grown to 15, 20, or 30 decigrams, when they must have more substantial 

 food, such as earth worms, beetles, larva', maggots. * * This year I introduced my method of young 

 fish feeding in two trout-breeding establishments, as a test, in order by the result to make a repu- 

 tation for my method. Both establishments were in the habit of feeding horseflesh. The one fed 

 50,000 the other 80,000 fish-fry, so that in two years they were fish of 1 to 2 kilograms. By my method 

 both establishments used only one-seventh of the food formerly used, and the cost of food per kilo- 

 gram was reduced more than one-seventh. One increased its plant to 120,000, the other to 200,000. 



One of the "foodstuffs" reared by Mr. Von Scheidlin is the larvae of flies, and 

 it is interesting to note that his method is very like that practiced by Mr. Atkins 

 already referred to. Mr. Von Scheidlin tells me that as the result of 30 years' experi- 

 ence and experiments in fish-culture he is fixed in his belief that to obtain the best 

 results young fish must be fed until they are at least 1 year of age before they are 

 turned out to seek their own living, and certainly 30 years' experience should count 

 for something. 



