FISH PONDS ON FARMS, 15 
day standards. Fish may and are being successfully propagated in 
far less ideal environments, but more native ingenuity in such cases 
is required. This, however, is a common attribute of the American 
farmer, and any one who can mix balanced feeds, practice scientific 
grain breeding, or master the intricacies of modern farm machinery, 
need not hesitate for fear of failure to add fish culture to his daily 
routine. 
Summarizing the construction, these features should be provided 
for: 
1, Water-tightness, so that a small inflow will be sufficient. This 
will result in high temperatures during the summer months. 
2. A shallow area, from 18 to 30 inches deep, where the fish may 
nest. 
3. A deeper area, of 6 feet or more, for winter quarters. This 
will also be occupied by the adults in the summer, after nesting is 
completed. 
4. A fertile bottom for the growth of aquatic plants, upon which 
fish food depends. 
If these requisites, together with a suitable water supply, are pro- 
vided the fish will thrive. 
The accompanying drawings explain the types of intake and drain- 
age devices which have proved effective. These may be varied to 
meet the conditions encountered, and be constructed of either wood or 
concrete. The latter material is shown in the illustrations, and is the 
most durable, but wood will be equally as satisfactory while it lasts. 
AQUATIC PLANTS AND THEIR VALUE IN POND-FISH CULTURE. 
Frequent reference has been made to the necessity of vegetation in 
fish ponds. Its advantages are many. It serves as food and a harbor 
for the lowest forms of minute animal hfe. Each advance in the 
scale of life constitutes a food for higher forms, and in the guise of 
fish the fertility of the ground contributes to the food of the human 
race. 
Plants play an important part in the purification of water, taking 
up the carbonic acid gas liberated by decomposition and exhaling the 
oxygen essential to living creatures. They thus prevent the asphyxia- 
tion of fish life, and act as a corrective of many abnormal character- 
istics of individual waters. 
Losses of fish through the depredations of enemies will be greatly 
lessened where there is an abundant aquatic growth in which they 
may hide. It furnishes a grateful shade on bright warm days, and 
the interlacing roots so bind the bottom soil as to prevent turbidity 
from casual disturbances. 
The aquatic flora of a locality varies greatly with its latitude 
and is also governed by the chemical ingredients of specific waters. 
The most desirable species usually thrive best in waters of limestone 
86497°—17—16 
