A small stone should be tied to each bunch of plants, to anchor them till they take root.
After your aquarium has been in operation a few days, a green coating will begin to form on the glass. This is a minute plant that is developed by the action of light. It can be removed by means of a swab. In all other parts of your aquarium allow it to grow, as it is the favorite food of gold-fish and snails.
SNAILS.
I have given drawings of the two best kinds of snails. One is shown with its broad foot expanded, by which it moves along the surface of the water, or on the glass when eating the green coating spoken of. Snails also eat decaying vegetable matter.
For keeping the water very clear, introduce a small-sized fresh-water mussel. Give him at least two inches of sand, in depth, in a corner of the tank, to burrow in, but watch him well, for if he dies without your knowledge your aquarium will be ruined.
CADDIS-WORMS.
In the illustration are figured three kinds of caddis-worms. These worms are useful for consuming decaying animal matter. When a "cad" has grown too large for his house, he makes a little case of silk, which he covers at each end with pieces of leaves, wood, or straw, biting them to the right length; some fasten on small bits of stone and shells. However rough the outsides of their houses may be, the insides are smooth, and lined with silk. When he changes into a chrysalis, he crawls up a plant, and closes up both ends of his house with a strong net-work of silk, which allows the water to pass through, but prevents the entrance of enemies. As he has taken care to place himself near the surface of the water, he easily escapes when he comes forth a four-winged insect resembling a small moth.
