94 FISH PONDS ON FARMS, 
The erappies spawn in comparatively deep water on isolated nests. 
Owing to their color, the depth of the water, and its usual turbidity, 
but few observations have been made of their peculiar character- 
istics at this period. 
Rock bass and warmouth bass deposit their eggs on gravel beds of 
greatly varying diameters, and their spawning instincts are some- 
what similar to those of the black bass, though in a less marked 
degree. ; 
By reason of their intrepidity at the time, all of the species referred 
to appear to be very tame while guarding their nests, but this instinct 
should not be presumed upon by permitting unnecessary disturb- 
ances about the beds. 
The incubation period of eggs of the various pond fishes ranges 
from a few days to two weeks or more, depending upon the mean 
water temperature. A drop below 55° F. is invariably fatal, while 
the percentage of hatch below 58° F. is greatly reduced. 
Under uniformly favorable conditions healthy eggs will hatch 
without any loss to speak of, but the average hatch of domesticated 
stock is not over 50 per cent. This, however, is a sufficiently large 
percentage to make pond-fish culture profitable. 
CHARACTERISTICS OF THE YOUNG FISH—THEIR FOOD AND 
GROWTH. 
When first hatched the fry of most of these species are colorless, 
and because of their tendency to collect among the roots and in the 
crevices of the spawning beds are difficult to find. They become 
darker in a few days, however, and are easily distinguished. In a 
short time they rise a few inches off the bed during the day and re- 
turn to the bottom at night, increasing the distance each day until 
they eventually reach the surface. During all this time the parent 
fish has given them the same sedulous attention as when they were 
in the egg stage. Gradually the school enlarges in circumference to 
such an extent that he has difficulty in keeping his brood together. 
He crowds them into shoal water—their natural feeding ground—and 
patrols the shore in an effort to ward off enemies, but they finally 
separate into small bands, escape the vigilance of their guardian, and 
become free lances in the strife for survival. 
The largemouth black bass and catfish fry school mach longer 
than the other species mentioned; in fact, catfish fry retain this 
gregarious tendency throughout oe first year, while young black 
bass remain together until 2 inches or more in length. 
Young sunfish and catfish are easily taught to take artificial food, 
when the natural food of the pond is insufficient for their nourish- 
ment. As with the adult fish, animal tissue is the most readily ac- 
