Fish 
AQUARIA 
LENTIFUL are the kinds of aquaria, from 
those made in jelly glasses and fruit jars, 
for the caging and rearing of water insects, 
to the larger aquaria for fishes. The 
aquarium may be a tank or a glass jar, 
but it should always have straight sides. 
The curved sides of the globe do not allow 
water to come sufficiently in contact with 
the air. If we have only water in the 
aquarium, we then need to change it quite often to 
keep our pets alive. But if we can plant in our 
aquarium the weeds which grow in ponds, through 
them, and the oxygen they give off, the water remains 
pure, and does not need to be replaced. This is 
called a balanced aquarium. 
To make a balanced aquarium we place in our jar, 
of whatever size or shape, a layer of sand, and from 
the nearest pond, or quiet pool in a stream, we bring, 
carefully, in a pail of water, such plants as we find 
living entirely beneath the surface. We select 
some of these and plant them in the sand at the 
bottom of our jar; after they are planted we put 
a few small stones upon them so as to hold them fast 
in the sand. Now our aquarium is planted, and we 
must add the water very gently, by letting it run 
down the side of the jar so as not to tear up the 
plants we have just put in place. Such an aquarium 
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