CuHapPTeR XVIII. 
THE CARE OF GOLDFISH IN AQUARIA. 
An aquarium may be made of any water-tight vessel, the material 
of which will not alter the qualities of the water by impregnating it 
with anything that would stain it or give it an offensive odor, either 
of which would be detrimental to the health of the fish. 
The shape of such a vessel is usually determined by the require- 
ments of the duty it is expected to perform, and should not, therefore, 
be wider at the top than at the bottom, for then the fish would leap 
out; neither should it be too narrow at the upper part, for this would 
exclude the atmospheric air by a reduction of the water surface. 
The old-fashioned fish-globes are about the worst vessel that can be 
selected for the keeping of goldfish as pets; they will do well enough 
for a temporary display of the fish, but for permanent use they may 
be compared with the Black-hole of Calcutta. Besides they are 
extremely dangerous, in regard to their round shape, as there are 
several cases on record where fish-globes, hung near a window, set 
fire to the lace curtains or the carpet, the globe acting like a con- 
densing lens. 
When the vessel in which to keep the pets has been selected, it 
is thoroughly cleansed with water only, the bottom is then covered 
with well-washed river, or white sea-sand, to a depth sufficient to 
allow the planting of one or more varieties of aquatic plants. The 
number of these from which to make a choice selection is large, but 
70 
