How to obtain tt. 239 
learned by experience ; the knowledge certainly cannot be gained 
from books. When the fish come up for their food with a good 
appetite, as they will if left long enough between meals, it is a 
good sign, and they may be freely fed. The distribution of the 
food should be managed carefully, and not too much given at one 
dip of the feeding box. Much care is required that no food is 
allowed to go to the bottom uneaten. Should it be allowed by 
any accident to get there, it must be carefully removed, which 
may be done by means of a fine gauze net. Sometimes, when the 
feeding of fry is managed by beginners, the bottom of a pond is 
allowed to get covered with uneaten food. I have seen such 
cases, and what has happened may happen again. Should such 
an occurrence as this take place it would be very difficult to 
remove all the food, and if nothing be done it will assuredly 
pollute the water, and probably produce disease, which may soon 
play sad havoc amongst the fish. 
The best thing to do in such a case is to scatter a little 
finely-sifted earth over the pond. It will settle on and about the 
offensive matter, and if this be followed up by a good covering of 
clean gravel, the bottom will once more be rendered clean and 
pure. Earth is an excellent thing to use occasionally in the 
ponds. It is good for the fish, and is such a powerful deodoriser 
that it tends to absorb, and so keep down any impurities that 
may exist. It is often desirable to use it in the rearing boxes 
before the fish are turned out of the hatchery. Some good 
clean earth should be selected. A few sods from a good old 
pasture are the best, and, to use them, they should be put into a 
tub full of water and well stirred and shaken, so that the earth is 
washed out of them. Then the liquid may be poured off into the 
pond, or the inside boxes, as the case may be. Pour it off care- 
fully, and if screened through fine perforated zinc so much the 
better, as this prevents lumps and fibrous or rooty matter going 
into the pond. It is only the muddy water which is required, and 
there need be no fear in using it freely. 
I have often watched the effect of doses of earth given in this 
way, and have found them to be highly beneficial. In a natural 
stream a considerable quantity of earth comes down with the 
water every time there is a freshet, and in the rearing boxes and 
