46 THE GOLDFISH AND ITS CULTURE, 
The work that is performed by trees, etc., on land is per- 
formed in the water by aquatic plants, Aquatic animals require 
oxygen for the same purpose as do land animals. Where no 
aquatic plants are at work to absorb the impurities from the 
water and replace the oxygen consumed by the animals, the 
current in the water, the waves caused by sume force, or a 
fall, relieve the water of the foul air and, by the marked faculty 
of the water to absorb, it is recharged with the life-giving gas 
from the atmosphere, 
As we have no current, no waves, nor a waterfall in our 
aquarium, we depend entirely on the action of the aquatic 
plants to make our aquarium tenable for its inmates. 
It is true most aquarium plants now under cultivation were 
originally collected by some one in their natural haunts as 
“weeds,” but does this not apply .to the plants the florist 
grows for our window garden as well? To speak of aquarium 
plants as ‘‘ water-weeds”’ is, to say the least, incorrect, and one 
could, with the same propriety, call the precious gems, used 
in jewelry “gravel,” because they were simply picked up as 
pebbles in creek- beds by Indian women and children. One 
must not forget that all these plants had to be acclimated 
and carefully cultivated to bring them to their present high 
standard. No matter how beautiful and costly our tank may 
be, without their co-operation it will be a burden to us instead 
of a source of pleasure. 
In addition, their decorative character makes them very 
precious to a collection. With a judicious arrangement of them 
in connection with the rock-work, and due attention of lights 
and shades in the planting of our aquatic garden, landscape 
effects can be produced that any master would be delighted 
to reproduce on a canvas. The foliage being so manifold and 
