XXIII -WHAT DOES A FISH COST?* 



By Christian Wagner. 



After the tiny, jelly-like fish, has left its egg it receives nourishment 

 for several days from the adhering yolk-bag, mostly resting on its side 

 upon a blade of grass as near as possible to the surface. Thence for- 

 Tvard, however, it preys on living aquatic animalculae, and though en- 

 joying a life scarcely perceptible by means of a microscope it soon begins 

 to hunt for the mite-like water-fleas, the larviDe of gnats, &c. For some 

 time I have been in the habit of keeping, and not only during the breed- 

 ing season, small cups and larger dishes for raising different insects, 

 which facilitate the observations. 



The goldfish, carp, tench, &c., are quite voracious when only eight 

 days old. They consume in three days about as many of these animal- 

 culse as their own weight. Higher or lower temperatures are at this 

 time of the greatest influence. The warmer the weather the greater is 

 the vitality of the fish and the more rapid its growth, if properly fed. 



By continued natural feeding the little fish doubles its size in about 

 eight days, and then, fourteen days old, is looking for larger food, which 

 now mostly consists of larvte of gnats. The consumption of food equal 

 to one- third of its own weight per day is still continued ; but the growth 

 does not progress at the same rate, it only increasing about 100 i^er 

 cent, in the next fourteen days. A fish of four weeks, with sufficient 

 food, will, perhaps, in four weeks double its size ; then in eight weeks, 

 and so forth, at the same ratio, if the winter or other circumstances do 

 not interfere. 



Although our predaceous fish, the so-called winter-fish, as pikes (pike- 

 perch), trout, &c., down to the little stickleback, sometimes take food in 

 rather cold weather, the so-called summer-fishes (carp, tench, bream) 

 eat almost nothing in winter time. The colder it is the slower they 

 breathe, and though on warm sunny days they occasionally appear near 

 the surface, they rarely take adequate food. They are always satisfied 

 with the little nourishment contained in the water, which, by breathing, 

 is conducted into the stomach — it is true at the expense of their own| 

 bodies, for in spring-time all these fishes appear more or less emaciated. 

 Suppose such a fish, one year old, be it summer or winter fish, to have 

 attained a length of about six centimeters, and to represent, accord- 

 ing to its weight, a food value of one pfenning [equal to nearly one- 



* Trauslated by H. Diebitsch from Deutsche Fisclierei-Zeitung, No. 46, Stettin, No- 

 vember 12, 1878. (JQ5 



