60 How to obtain tt. 
desirable, after filling the pond, to cultivate it properly, and to 
bring it into a suitable condition for receiving the stock of fish 
that is to inhabit it. Asa farmer must provide a supply of food 
for his sheep before turning them into a field, so we must provide 
for our fish. = 
Trout are carnivorous, and if we examine the contents of” 
their stomachs we shall find that the creatures on which they have 
been largely feeding are mainly dependent upon a crop of 
vegetable food. If they are to exist in sufficient numbers to form 
an adequate supply of food for the fish that prey upon them this 
must be provided. Therefore, it follows that by judiciously 
cultivating suitable plants a sufficient food supply can be main- 
tained, other things of course being equal. Should this fodd 
supply not be in existence naturally in the water it must be 
introduced, and regarding its introduction, and the introduction 
of aquatic vegetation, I shall have more to say later. 
Where the water supply is of a limited nature, it will do 
better work and go further in a deep. pond than in a shallow one. 
It is obvious that in a pond of considerable area, but only running 
three feet or so in depth, the water will be more affected by the 
rays of the sun, and in summer will rise to a higher temperature 
than in a pond of smaller area but which is eight or ten feet deep, 
or perhaps more. The pond of smaller area, but greater depth, 
will support a larger quantity of trout during such a period than 
the shallow one. 
It also often happens that in addition to the visible water 
supply running into a pond there are springs in the pond itself, or 
there is a considerable quantity of water percolating through the 
soil, and this alone is a very valuable help to its trout producing 
capacities. In the deeper pond there is a greater probability of 
such an additional supply. I have known ponds which have thus 
been fed by copious springs, but which have possessed no visible 
water supply, that is to say, that there was no stream running into 
them, and yet they have proved capable of maintaining a nice 
head of trout. Sometimes we find a pond from which there is a 
considerable overflow, but no stream apparently feeding it. In 
such a case there must be springs, and such a pond may do for 
trout. Occasionally in ponds of this nature, however, the water 
