248 
BULLETIN OF THE UNITED STATES FISH COMMISSION. 
and smothering in any i)art of the trough. If it is necessary to hatch a much larger 
number in one trough, the sliding screen should be so arranged that the water will fall 
well up against the end of the trough. This can be done by raising the screen and 
turning it back against the reservoir, or by putting iu a wedge-shaped block for the 
water to fall upon, turning the thin side of the block to the upper end of the trough. 
I have had 50,000 trout hatch in one trough prepared iu this way, without any loss 
from suffocation. I would not, however, recommend hatching such a number together 
in one trough, if it can be avoided, as there will be too many to raise up to feeding 
time, and they would necessarily have to be divided before that time. 
The young /r^.— After the fry hatch out they will require but little attention until 
the yolk sac is absorbed and the time of feeding comes on. They should be examined 
each day, and the dead fish and other decayed matter removed from the troughs. 
The troughs should be kept perfectly clean and jnovided with a thin layer of coarse 
white sand on the bottom, which will serve iu keeping the fish clean and in a healthy 
condition. As the fish grow they should be thinned out in the troughs from time to 
time, as their size may require. When they first begin to feed, 12,000 to 15,000 fish 
to the trough will not be too many ; but by the time they get to be 1^ to 1^ inches long 
they should be divided up, 8,000 to 10,000 to the trough, while with yearling fish, or 
fish averaging 3 inches in length, from 3,000 to 4,000 will be as many as one trough 
will carry. More room would be advisable in all cases if it is to be had. 
Food of young trout . — Beef or sheep liver, ground or chopped to a fine pulp, is 
generally recognized as being the best artificial food for young trout. Other things 
have been tried, such as hard-boiled eggs grated fine, milk curds, etc., but liver seems 
to be the favorite article at present. Some efforts have been made to jiroduce a 
natural or living food, but the results so far, I believe, have been unsatisfactory. 
This may yet be accomplished for late spring and summer feeding, but for feeding the 
fry during the first three or four months of their lives, which is in the winter season, 
I think we will have to be contented with something besides a living food, and for this 
imrpose I can recommend nothing superior to the liver diet, unless it be fish eggs. 
Fish eggs as food . — During the siiring of 1895 the idea Avas conceived of having shad 
and herring roe put up in tin cans to serve as food for young trout. One case (2 dozen 
1-piut cans) was sent to me at Wytheville Station, but as I did not receive it until the 
first iiart of June, and my fish were then all good-sized fingerlings, I was not successful 
in getting them to eat it at that time, as they seemed to be looking for something 
larger than herring roe. I concluded then that I would keep over a few cans and try 
it the following season (1895-95), AAdiile the fish were yet small. This I haAm now done, 
and the result has been Am.ry satisfactory. I am sorry that I did not have enough roe 
this season to prosecute the experiment further; but my experience has been sufficient 
to convince me of its merits and to cause me to belieAm that it is a more wholesome diet 
for young trout than liver, since it does not pollute the Avater iu feeding and the fish 
grow to be extremely fond of it. I am of the opinion that fish roe will hereafter form 
a good part of the food for young trout that are reared in confinement. I understand 
that it can be gotten during the fishing season in large quantities. 
Feeding the fry.—lw my opinion the feeding of young fry is the main point in suc- 
cessful trout-breeding and the part in which we are most likely to err. I believe that 
more young trout die from improper feeding than from all other causes put together; 
and the reason for it consists in too much haste in feeding or else iu distributing 
