NOTES ON FISH-CULTURE IN GERMANY. 
315 
fat. Of slaughter-house refuse, the liver and lungs are the most important, and both 
are excellent. It is urgently recommended that only such food should be bought as 
has passed the inspection of slaughter-house inspectors. Large pieces of animals 
which are not suitable for human food are also dangerous for lish, and only when they 
have been boiled (as is done in some slaughter-houses) so as to bind the albumen 
contained therein, is it advisable to use them. 
Both salt-water fish and the refuse from the slaughter-houses are ground tine 
in a machine made for the purpose (for establishments of the average size I would 
recommend No. 91, by Scheft'el & Schiel, Miihlheim-on-the-Rhine, which, worked by 
hand, grinds 100 pounds in an hour) and then mixed; an addition of shrimp flour or 
meat flour is useful and gives consistency to the food. 
According to my experience, 5 to 6 pounds of such food will be required for 1 
pound of fish, provided the water is kept at the proper temperature — char, 12° Reau- 
mur (59° F.); brook trout, 14 to 16° Reaumur (03.5° to 68° F.); rainbow trout, 16° to 
18° Reaumur (68° to 72.5° F.) — which temperatures can easily be maintained if the 
direction in which the sun strikes the ponds and the flow of water through the ponds 
are carefully calculated. The cost of raising 1 pound of fish, including cost of admin- 
istration and culture will in an average-size establishment be, at the very highest, 
90 pfennig (21 cents) per pound. For fish weighing from 1 to 5 pounds the cost of 
rearing will be still less. 
It is also recommended to use snails, caterpillars, etc., for fisli-food. They will 
form an excellent addition to the above-mentioned articles of food. Even if the expense 
of collecting is rather high, I would give my fish nearly all the food of this kind 
which could be obtained. 
The trout is a very voracious fish. An average establishment which has, e. g., two 
ponds of 4,000 young fish and intends to produce with these 8,000 fish, with a total 
weight of 2,000 pounds, will during one campaign have to procure 10,000 to 12,000 
pounds of food, or on an average 240 to 250 pounds of food per week (say 200 pounds 
of fish and 50 pounds of slaugliter-bouse refuse). Even in summer fish-food can be 
kept sufficiently fresh for three days if placed in large earthen crocks, covered wflth a 
little salt, and washed by running water. Even average establishments will therefore 
be able to procure twice a week a 100-pound basket of salt-water fish by railroad. 
It is quite evident that, food being so cheap, a profitable intensive culture is 
possible. The greatest danger to be feared is the possibility of epidemics; this danger 
can not be entirely eliminated, but I am justified in saying that (1) healthy food, (2) 
a sufficient supply of aquatic animalcula for destroying the refuse in the ponds, (3) 
ponds dug out from the ground which, after every campaign, are cleaned (both bottom 
and slopes), well supplied with watercresses, and laid dry periodically, will form efficient 
preventives of epidemics. 
In summer the fish should be fed about sunset, otherwise shortly after noon, and 
they should never get more food than about 5 per cent of their average weight. They 
ought not to be fed in sultry weather nor when the temperature is considerably above 
22° Reaumur (81.5° F.). 
I strongly object to feeding-tables in these ponds. The food ought to be thrown 
to the fish with a ladle, and so little at a time that they catch it before it sinks to the 
bottom of the pond. In using feeding-tables there is danger that the attendant, from 
sheer laziness, will pour the entire quantity on the table at once, thereby causing the 
