46 THE AQUAVIVARIUM. 



fish. They are subject also to great varieties in 

 their fins. Sometimes the dorsal fins are double, 

 and the caudal fins are divided into three parts, so 

 as to give them the appearance of having triple 

 tails. When this latter circumstance occurs, Mr. 

 Yarrell has observed that they are deficient of 

 dorsal fins. In the winter it is well occasionally 

 to feed all fish, as at that season the plants in the 

 Aquavivarium do not grow very fast, and there 

 are few or no animalcules produced. Gold fish 

 may be fed on bread or biscuit. Many of the other 

 fishes will prefer a little piece of raw meat or small 

 worms. The one thing most necessary in feeding 

 fish is to avoid giving them more food than they 

 eat. If too much is supplied, the animal or vege- 

 table matter will easily decompose, and set the 

 contents of the whole jar in a state of fermentation. 



Another form of carp, which, although not much 

 known 'to the angler, has become better known 

 since the introduction of the Aquavivarium, is the 

 Prussian Carp (Gyprinus gibelio). This fish is found 

 in ponds in the neighbourhood of London ; and on 

 account of its peculiar habits, and tenacity of life, 

 is well adapted for the Aquavivarium. Although 

 not so bright a fish as the golden carp, the back has 

 a golden metallic lustre, the eye is golden-yellow, 

 the belly is white, and the fins are of an orange-red 

 colour. It is sometimes called the Crucian Carp, 

 but Mr. Yarrell has confined that name to another 

 species (C. curassius) which has been much less seen 

 in this country. 



The MINNOW, MINCE, or PINK, Fig. 6 (Leuciscus 



Fia. 6. 



