MANUAL OF FISH-CULTURE. 99 



REARINGr AND FEEDINGr. 



If the fry are to be reared for breeding, one week before the food-sac 

 is absorbed they are changed from the trays to a huge pan and removed 

 to the rearing-troughs. Gravel should not be used in these troughs, 

 as the uuconsumed food works down into it and, becoming fungussed 

 there, causes a greater spread of disease and increases the labor of 

 caring for the fish. 



The time to begin feeding the fry is readily ascertained by trial. If 

 they rise to minute particles of food thrown upon the water, they are 

 then ready for regular feeding. The time and frequency of feeding 

 young fish, the kind of food, and the manner of feeding them, are of the 

 greatest Importance. Liver gives better results than any artificial 

 food, and its jireparation is very simple. Beef livers are ground by a 

 meat-chopper and then strained through a fine-meshed screen, a thick 

 pudding being made by the addition of water. A small portion, only 

 such an amount as the fish will readily eat at a time, is spread upon 

 the surface of the water with a feather, and they are fed as often as six 

 or eight times per day until they become used to the new diet. As 

 tiiey grow older the quantity of food may be increased but the fish are 

 fed less frequently. At this stage the young fish have such a i)reca- 

 rious hold upon life that too much attention can not be given to their 

 care. Not more than 20,000 can be held with success in a feeding or 

 rearing trough, and a regular stated supply of water is kept flowing 

 tlirough to prevent disease, and the fish are properly thinned out in 

 order to prevent loss by suftbcation when they increase in size. About 

 30 gallons of water i)er minute are suflficient for 20,000 fry, though this 

 ♦piantity is increased as the fish grow stronger and are able to breast a 

 heavier current. 



In the spring season, when the water begins to grow warm, the fish 

 re(juire more room than the feeding-troughs aftbrd, and it is then nec- 

 essary to transfer them to ponds. The North ville rearing-ponds are 

 5 feet by 20 feet, made from 2-inch pine boards and provided with a 

 gravel bottom. A pond of this size accommodates from 10,000 to 20,000 

 fry till the middle of the summer, when the number is reduced to as 

 low as 5,000. It is advisable to place not more than 5,000 in the pond 

 lit first to avoid the labor of reducing the number of fish at different 

 times, and also because crowding into too small a space retards their 

 growth. 



At first the fish require coaxing to induce them to eat, as the change 

 to their new abode has frightened them, and a great deal of i)atience is 

 necessary in their treatment. They are fed at regular intervals three 

 times per day. As their appetites are poor for the first few days, the 

 liver will fall to the bottom and foul the pond, if great care is not exer- 

 cised, and three fourths of an hour is not too long for feeding 5,000 fry. 

 The time occupied in feeding is diminished and the amount of food 

 increased according to the judgment of the fishculturist; but their 

 appetites should never be completely satisfied. 



