THE GOLDFISH AND ITS CULTURE, 65 
this is no cause for alarm. The water is then undergoing its 
natural metamorphosis, and it will, in a day or two more, be 
as brilliant as crystal. When water loses its brilliancy, turn- 
ing milky, and the fish remain near the surface breathing 
atmospheric air, the fish may be overfed, and the surplus 
food, or something else in the tank, is decaying. Find the 
cause and remove it. Add a good pinch of table salt to the 
water and aerate it by dipping it up with a cup and splash- 
ing it from a height of about 18 inches back again. Do this 
for five or ten minutes and the fish will feel relieved. Stop 
feeding for two days also. When water turns greenish it has 
too much light. Shade the tank with blue paper until it 
clears, and regulate the window shades better after that. Clear 
water turning flaky is a sign of an approching storm. 
Should an aquarium tank be filled up to the top? This 
depends on the style of the casing or frame of the tank. An 
ordinary plain-framed or all-glass tank should not be filled to 
the top. It does not look right and endangers the fish, which 
will accidentally leap out. When the style of the frame is 
such that it may form a guard above the waterline, then it 
should be filled to the top (see plate V.). 
Tuffstone is a calcarious deposit over groups of reed, 
grass and moss, ages old. The vegetable matter having dis- 
appeared, nothing but the picturesquely-formed deposit is left. 
It is found a few feet below the surface of the earth, near 
the river Rhine and in Thuringia (Germany), not far from my 
birthplace, and also in the northern part of Ohio. The color 
varies, running from a light grayish-brown to a rust color, 
according to the locality where it was found. The best speci- 
mens for our purpose come from Thuringia, being of good 
