FISH-BREEDING. 479 



any anmiai matter thrown in only serves to make the water 

 impure, and of course affects the health of the fish. 



FEEDING-TROUGHS. The depth of water in the feeding- 

 troughs need not be more than four inches, and the area pro- 

 portioned to the number of fish. M. Coste says he was ena- 

 bled to feed and bring up in a space of twenty -one inches 

 long, six wide, and three deep, as many as two thousand 

 young Salmon at once. This seems improbable ; the space 

 is certainly more circumscribed than necessary. A trough 

 of eight feet long and four feet wide would no doubt be suffi- 

 cient for that number of young Trout during the first three 

 months, at which time they will likely be from two to two 

 and a half inches in length. They could then be transferred 

 to ponds, the size of which may be about eight yards wide 

 and twenty -four long, which would cover nearly the twenty- 

 fourth part of an acre. According to such calculation, it 

 will be seen that a single acre divided into twenty-four ponds, 

 would sustain forty-eight thousand Trout during the first 

 year. 



FOOD FOR YOUNG TROUT. After trying several kinds 

 of food for young fish, I have found none so readily received 

 or divisible into small particles as fish-roe. On crumbling it, 

 after being fried or boiled, into an aquarium, the smaller fish, 

 especially those of a predatory species, seize a single egg 

 greedily before it falls to the bottom, and the Goldfish hunt 

 for it industriously amongst the gravel, and leave none to 

 affect the purity of the water. I would therefore recommend 

 it as preferable to any other, where it can be had ; if not, 

 boiled meat of any kind (as I have also ascertained from 

 experiment), when cold and crumbled in small particles, is 

 the best substitute. It is better to give a less quantity than 

 the young brood can consume, for reasons already stated. 



