
THE FRESHWATER AQUARIUM AND ITS MAINTENANCE 
be put in the water, least of all after smoking; the aquarium should be 
covered when sweeping, and the room frequently aired or ventilated in mild 
weather. The dust may be removed from the surface of the water with 
a piece of clean blotting paper, but it soon settles to the bottom and 
serves as food for the scavengers and formsa part of the humus or residuum 
on the sand or pebbles. When the humus layer becomes thick, it may 
be injurious, and should be removed with the dipping-tube, the water 
siphoned, or the aquarium cleaned. In an experimental aquarium con- 
taining twenty gallons of water, this humus had formed fully halt an inch 
thick, the water not having been changed for eighteen months, yet the 
fishes were perfectly healthy and contented. It is best to remove it, how- 
ever, as it is the culture medium of parasites and fungi, and it is not 
advisable to leave it so long in the aquarium. 
A piece of charcoal floating on the water or weighted and hidden 
among the plants serves as a deodorizer and mild antiseptic, and can be 
introduced to advantage. 
Atc#. Algz on the glass may be removed with a brush or a piece 
of felt on a stick or rod. It is advisable, however, to leave it on the sides 
which do not obstruct the view, as it aids in screening the fishes from ex- 
cessive light and in keeping the water in good condition. A fish showing 
signs of illness, will often speedily recover when removed to a tank filled 
with green water, as it contains not only desirable food, but also beneficial 
medicinal properties. A very little permanganate of potassium will check 
the growth of Alge, if this is found to be objectionable. 
Destruction or Piants. Even when sufficiently fed, the fishes 
will sometimes tear and destroy some of the aquatic plants, feeding on the 
younger shoots; but this is often done in sheer mischief and wantonness 
and the remedy is to introduce more of those plants which are unmolested. 
It may also be noticed that the fishes take the sand and smaller pebbles 
into their mouths; they do this to feed on the tiny water plants growing 
upon them, and it is not always an indication of insufficient feeding. 
In conclusion it would be well to recapitulate the principles leading 
to success with the properly conditioned aquarium, any mistakes of which 
will surely lead to failure:—absolute cleanliness with everything pertaining 
to the aquarium; proper and abundant light; a vigorous growth of desir- 
able aquatic plants; absence of decaying vegetation, a proper balance of 
plant and animal life, with preferably a preponderance of the former, ab- 
sence of parasites and diseases, sufficient scavengers; and care in feeding 
the proper food. 
ao 
