MARINE AQUARIA 
Freshwater aquaria are familiar household objects, but the Marine 
aquarium is known to the general public only through the exhibitions at 
World’s fairs or those in some of the larger cities, as in Castle Garden, 
Battery Park, New York; the Vivarium of the University of Pennsylvania, 
at Philadelphia; and the Grotto of the Fish Commission Building, at 
Washington, D. C. 
It is a general opinion that the marine aquarium is difficult to estab- 
lish in the household, though it is really easier to maintain, when properly 
installed, than those of freshwater, as ventilation, good light and sunshine 
are not as important; they are even to some extent objectionable, as strong 
light is likely to produce an excessive growth of alge, and oscillatoria, 
which may cause turbidity in the water, and the marine fauna is more 
comfortable without much light, as in the ocean they obtain comparatively 
little. 
AkERATION. ‘The necessary aeration is not produced by the growth 
of plants, as is the case in the freshwater aquarium. The marine flora 
cannot be kept in fine growing condition under any circumstances, and 
may be largely dispensed with, its purpose being more to enhance the 
beauty and add to the natural appearance of the aquarium than to serve 
as oxygenators. The all-important necessity is an efficient artificial aera- 
tion, and some little experimentation is necessary that the introduced air 
is evenly distributed at all times, and in sufficient quantity to satisfy the 
requirements of the animals without excess and overstimulation. The 
correct amount under varying conditions is soon learned. The air should 
be admitted along the rear of the aquarium as a heavy fog, not in small 
bubbles to burst on the surface. More air must be introduced when the 
water is warm than when it is cold, as at higher temperatures less is ab- 
sorbed by the water, while the animal requirements are greater, they 
being then the most active. 
The simplest and most efficient aerating device is the cylinder and 
pump described on page 178; and which should be kept in constant opera- 
tion, though care should be taken not to over-aerate the water. 
Another simpler aerating device consists of a flowerpot or jardinaire, 
having the bottom hole plugged with a piece of sponge and suspended 
over or supported on the frame of the aquarium. Into this some of the 
water is filled and in perculating through the sponge is both cleared and 
aerated. It fully answers the purpose for shallow smaller tanks. 
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