THE CARPS 105 



For the first eight or nine days the young roach 

 grows exclusively at the expense of the food in the 

 yolk sac, but about the ninth day the mouth becomes 

 open, and he commences to feed, the food in the yolk 

 sac now being practically exhausted. 



At three weeks old the larva has grown to more 

 than twice the length he was when hatched, and the 

 gas bladder is now sausage shaped. 



At the end of three weeks a bud appears at the 

 right-hand top corner of the single-chambered gas 

 bladder. This bud rapidly increases in size, and within 

 a week has formed the front half of the constricted gas 

 bladder of the roach. A glance at the photographs 

 facing p. 106 will illustrate this point better than 

 further description. 



At six weeks the roach is almost a perfect fish, and 

 only the rudiments of the primitive fin remain. Plenty 

 of food is now all that he requires, and until the autumn 

 the larvae grow rapidly. With the cold weather, food 

 becomes scarce, the digestive juices in the stomach cease 

 to flow, and the growth of the fish is arrested until the 

 weather again becomes warm. At the end of the first 

 year, most roach fry are about an inch and a half in 

 length, though they may have grown to twice this size 

 under exceptionally favourable circumstances. 



The carp is not a fish of much importance in our 

 country, but in Germany its cultivation is systematic- 

 ally undertaken. Suitable carp food is bred in ponds, 

 liberally supplied with sewage. Into these ponds the 



