Fig. 4.. Unsorted stomach contents of a 7.1 cm. length brook trout from a natural 

 pond. Consisting almost entirely of small and large Chironomus larvae of various 

 kinds. The intestinal canal of the trout contained a total of 556 Chironomus 

 larvae, and 11 Cladocera (v;ater fleas) and Copepodae (hoppers). 



"Air feeding", i.e. feeding upon flying insects will play a role only during certain 

 periods, vfhen such a diet is available. Schaeperclaus (1930) found that caterpillars may 

 be an important item of the diet in tree-surrounded ponds, but the disadvantages of shade 

 certainly outv/eigh the advantages of additional "aerial" food supply. 



Pike. Perch-pike Catfish. The pike may be considered the most rapacious of all fish. 

 One-summer old pike, only about 20 centimeter (7 inches) long devour one-summer old carp 

 vdthout such ado nor difficulties. According to Scholz, pike will sv;allow chunks of from 

 20 to 30 per cent of their oth bodily v/ei^ht. Only medium and larger two-summers old carp 

 are safe from the attacks of these voracious feeders. Naturally, they will also go after 

 smaller dace, crucian-carp, smaller pike, perch. and even after frogs and rats, if they can 

 be caught at all. 



The yoxmg pike is an insectivor and as such has a preference for dragonfly larvae and 

 larger Crustacae, but their rapacity asserts itself in the first fev; days. In contrast to 

 pike, the perch-pike, even when grown up, vd.ll feed only upon small fish. He lacks in 

 agility to tackle larger fish and is also handicapped by its small mouth. 



Its predatory nature usually asserts itself only in its third year. In its first 

 yesT, the perch-pike feeds upon plankton and in the second year feeds upon the shore-life 

 and bottom-life of the pond. 



In certain parts of the country (Germany) the catfish is a bothersome nuisance and 

 like the stickle-back is hard to get rid of. Its prey is mostly small fry but he is also 

 suspected of preying upon spavm and fry. 



Crucian . Dace. Stickle-back , and Minnow . All these are small-fry feeders (including 

 their "gold" varieties), and they prey upon insect larva, crabs, mollusks and "aerial" 

 food, just like the main pond fish. The bleak may be excepted as feeding chiefly upon 

 plankton, while " Ploetze " (Leuciscus rutilus) and " Rotfeders " (Scardinius erj'throphthalmus) 

 feed also upon plants, 



3ut all of them are more or less bothersome pests, depleting the larder of the profit- 

 able species, so to speak. They are also quite often disease and parasite carriers and for 

 all of these reasons should not be tolerated. 



14 



