48 THE FRESH-WATER AQUARIUM. 
atus, Paludina vivipara, Lymnea stagnalis, putris, auricul- 
ata, and glutinosa, Physa fontinalis, Bythinia tentacula. 
Bivalves.—Anodon cygneus, Unio pictorum, tumidus 
and margaritiferous, Dressinia polymorpha, Cyclas corneus. 
CHAPTER VIII. 
GENERAL MANAGEMENT. 
FEEDING should be performed twice or thrice a week, 
_ and will be as amusing to the observer as gratifying to 
the fishes. Bread is not so objectionable as many have 
stated. Carp, bleak, and minnows eat it greedily, and 
soon grow tame if regularly fed with it. Most small 
fishes take insects, such as flies, spiders, ants, and soft 
larva, greedily; but the large fish disdain such diet. 
Small red worms, and white of egg, are good general 
_ foods, and seem highly beneficial. When feeding, see 
that the carp get enough, for they are slow fish, and get 
_ robbed wholesale by their more lively neighbours. Food 
_ not eaten will decay, unless speedily removed, hence care 
must be exercised on this head. 
Conferve.—When the tank has been established a few 
weeks, the inner sides of the glass will show signs of a 
green tinge, of a slimy nature. This is owing to the 
| growth upon it of minute forms of vegetation. If this 
is allowed to go on unchecked, the glass will in time 
| become opaque, and the view of the interior will be lost. 
Hence it must either be kept down in growth or occa- 
. sionally removed. 
Uses of Mollusks.—It is to prevent this rapid growth 
that water-snails are registered among the tenants of 
