had for two or three hours every morning. In summer the window should be opened, and in the winter evenings the tank drawn back into the room. A south window may be used for the aquarium if care be taken to shade off the noonday sun. When the water at the bottom of the tank becomes impure from the accumulation of sediment, it may be drawn off by a siphon (of rubber tube) without disturbing the water above, after which the tank must be filled up again with pure water. For the purpose of removing large substances from the bottom, a pair of wooden forceps—glove-stretchers will do—are required. Light particles, such as uneaten food, decayed leaves, etc., can be removed by placing against them one end of a small glass tube, and covering the other with a finger. The aquarium should be kept as clean as possible, all dead plants or animals being at once removed.
The best plants for fresh-water aquaria are the spiral Valisneria, a native of Southern Europe, and not easily procurable; the American water-thyme (Anacharis alsinastrum); the common frogbit (Hydrocharis morsus ranæ) which, being of different form from the others, will give variety in appearance; the arum (Calla palustris); common stonewort (Chara vulgaris); water-soldier (Stratiotes alvidies); spiked water-milfoil (Myriophyllum spicatum); small water-lilies (for larger tanks), white (Nymphea alba), and yellow (Nuphar buteum). A little duckweed (Lemma minor) may be added, as it floats about and harbors minute insects which the fish eat. In choosing animals for the same, the golden carp is most desirable for its beauty, the minnow for interest and longevity. The latter should be examined before admission
Fig. 4.
Marine Aquarium (Front View).
and rejected if a white downy spot is observed near the tail, as that is an indication of disease. The loach, the common carp, Prussian carp, roach, tench, and gudgeon, may be admitted, but the first three are preferable to the last. The common tadpole possesses considerable interest in its development into the frog. The small newt and the triton are objects of interest and quite harmless. The latter has a bright-yellow body striped with black. When amphibious animals, such as the newt and frog, are kept, the rock-work must rise above the
