390 BULLETIN OF THE BUREAU OF FISHERIES. 
distributed into two ponds. The more spacious the pond is, the better it is for 
breeding purposes. 
The best food for the young is natural food, viz, plankton, which is on 
that account cultivated beforehand. About as much as one koku (5.2 bushels) 
of rice bran, soy lees or the excrement of man or horse is put into the pond, if 
it is 50 tsubo (165.3 square meters) in size and over 10 years old. But,if the 
pond is only about 2 years old, a double quantity of the fertilizer is used. In 
each case, the pond is drained previous to putting in the fertilizer, after which 
its bottom is exposed to the sun’s rays for about a week, and then the pond is 
filled with water. Another pond of 40 to 50 tsubo (132.2 or 165.3 square meters) 
in size is provided for receiving thefry just hatched. This pond already contains 
the plankton which was produced by feeding the pond with about 3 to 4 to 
(1.5 to 2.1 bushels) of the aforesaid fertilizer. Besides, if 1 go (0.005 bushel) 
of mijinko is put into the pond three days prior to removing the fry there, they 
increase to an immense number in that short interval. 
When the young fish begin to swim about in the pond, the bundles on which 
the eggs were deposited are removed, and they are fed from the following morn- 
ing with boiled eggs (5 in number), prepared as in the case of the ranchu. 
Three or four days later, when it is warm, the water in the pond is drained off by 
means of a rubber siphon, as stated before, and the young are put into a mud 
pond and fed with mijinko. Ten or fifteen days after, the fish, having out- 
grown the size of the pond, have to be removed to another pond. When a 
supply of mijinko falls short in that pond, the fish are again put into a new 
pond where plenty of such food can be had. 
In order that the ryukin may be reared with any success, at least four 
ponds are required, two of which are intended for keeping the young and the 
other two for cultivating mijinko. In the middle of May the fish are grown 
so large that the larve of mosquitoes can be given them as food on earthenware 
plates slung by three strings from a bamboo pole. Given 800 parent fish, 
200,000 offspring are produced, which is a proper number for the capacity (200 
tsubo) of the four ponds just mentioned. 
No selection of the fish is yet made at this stage of their development 
(the middle of May). After feeding them for about fifteen days from earthen- 
ware plates, the selection is first made in the following way: Food being put 
into a basket or a scoop net, the young are thereby enticed and caught, and 
are distributed into two ponds. The first pond is at the same time completely 
cleaned from everything pernicious and replenished with water. The selection 
is sometimes made while catching the fish with a basket or a scoop net from 
the new pond, when an earthenware plate is put for this purpose into the basket 
(or the scoop net), the inside of which is covered with gauze. The caudal fin is 
