894 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



tion of the tench {Cyprinus tinca)^ no other kind of fish, however harm- 

 less, is allowed in the pond. The tench is related to the carp, but it 

 spawns 4 to 5 weeks later, so there can be no danger of cross-breeds. 



Great care should be taken that no gold-fish ( Cyprinus carpio auratiis) 

 or bream [hrama) get in the pond, for these fish would soon mix with 

 the carp and tend to degenerate the breed. Such fish should therefore 

 be removed or killed at once. The gold-fish, especially the milter, swims 

 in spawning-schools like the carp, and at the very same season. It thus 

 spoils the eggs of the carp, as all eggs which it impregnates will pro- 

 duce spotted fish, having at least a silvery streak ^ to ^ inch long and 

 ^ inch broad, between the caudal and the dorsal fin. Such bastards 

 (the cross-breeds of gold-fish and Garassius also resemble them) do not 

 grow larger than gold-fish, and have as many bones. They are unfit 



BA Cross-section of pond through breeding-place. 



for table-use and entirely unsuited for ornament, as they are neither 

 genuine carp nor gold-fish, and are disagreeable objects in the eyes 

 of the scientist or connoisseur. If such fish are not removed immedi- 

 ately the consequence will be another cross-breed during the next 

 spawning-season, for such a hybrid spawns, like the gold-fish, when it is 

 a year old, and the breed of carps would degenerate still more. It is 

 best to kill such worthless cross-breeds at once, as they are apt to give 

 great trouble. 



I would embrace this opportunity to impress upon every carp-culturist 

 who intends to make breeding-experiments with any carp procured 

 through the United States Fish-Commission, the importance of hav 

 ing if possible only one of three above-mentioned kinds of carp, unless 

 he can have every kind in a separate pond. Thus, the common 

 carp {Cyprinus carpio communis) should never be placed in the same 

 pond with the " mirror-carp" or the " leather or naked carp " {Cyprinus 

 carpio alepidotus, coriaceus vel nudus), nor should the two last-mentioned 

 varieties ever be in the same pond. Cross-breeds would invariably be 

 produced, and in such a manner that one would have neither genuine 

 common carps nor genuine mirror or leather carps, but a cross-breed of 

 all the three varieties. Not even when quite young and not yet capable 

 of spawning should these varieties be put together, because, even if 

 they are kept strictly separate during the spawning process, the young 



