20 IN. 

AQUARIUM CONSTRUCTION 
In the construction of an aquarium the first consideration should be 
the comfort of the animal inmates, then the production of a pleasing form, 
with sufficient strength to insure against leaks or breaking of the glass by 
the water pressure. This latter, as previously mentioned, frequently 
occurs with all-glass aquaria, and has led to the more general adoption of 
brass and iron-framed aquarium tanks. 
Aguarium Proportions. Surface aeration being necessary to the 
survival of all forms of aquatic life, the aquarium should be constructed to 
have large surface dimensions, greater than the depth of the water; even 
oy 1O1N. 
20 IN. 

w 
FIG. 235. 
though its appearance may not be quite as pleasing as the usual high and 
narrow forms, designed to offer the largest field of view, to occupy the 
least space, and to restrict the weight of both the aquarium and its con- 
tents. To test the importance of surface aeration, a few freshwater fishes 
may be placed into a shallow dish of water and the same number into a 
high and narrow jar containing the same quantity of water, when it will 
be observed how soon those in the latter receptacle will come to the 
surface gasping for air. The diagram, Fig» 235, shows three vessels, 
each containing 1000 cubic inches of water, the first having a surface 
area of 50 square inches, the second 100 square inches, and the third 
200 square inches. No. 3 will support at least twice as many fishes as 
No. 2 and four times as many as No. I. 
The length of an aquarium may be proportioned to the available 
space, but the breadth should not exceed 24 inches; when greater than 
this the contents will be somewhat obscured. The depth of water 
should not exceed 20 inches, because the pressure of the water would cause 
discomfort to the inmates and tend to confine their movements to the 
upper part of the aquarium. Large shallow tanks always give the best re- 
sults. When space is available and the light is on the surface, a nearly 
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