The plant life of a water garden grows at three levels. There are submerged or oxygenating plants beneath the surface; floating plants on the surface; and in the surrounding ground, slightly above water level, the marsh and bog plants.

Some submerged and some floating plants must go into your pool, since goldfish do very poorly without them. Border plants are necessary only to please the eye, but they are important, too, for water-lilies are twice as beautiful with a background of accessory aquatics.

The simplest way to select aquatics for the health and beauty of your pool is to leave it up to your water-lily dealer. Almost everyone offers standard assortments of submerged, floating, and border plants. These are well balanced, in both variety and quantity, and you have only to order a large assortment or a small one, depending on the size of your pool. If your dealer does not advertise such assortments, you can give him the size of your pool and ask him to make a selection for you.

After you have tended your water garden for a season or two, you will have your own ideas, likes and dislikes, and will be able to order aquatics thereafter in more specific terms. If you have a neighbor with a water garden, you can enlarge your collections by trading cuttings.

In assembling this listing of aquatics to recommend to you, I drew from the catalogs of what I consider the twelve leading dealers in the United States. I omitted those few rare plants, which they have for sale only on occasion, as well as those which grow only in the cool waters of the northern United States and southern Canada, and the tropical and semitropical plants which thrive only in the hot and humid South. The aquatic plants which remain are those that you can order from practically any dealer, and those that will thrive in practically any section of the United States.

These plants keep pool water healthful by releasing oxygen into it and taking from it carbon dioxide, which, in strength, becomes poisonous to fish. These oxygenators can be seen at their work frequently in patches of strong sunlight, particularly when they are producing an overabundance of oxygen. Tiny, silvery bubbles form on the submerged foliage, break away, and rise to the surface.

Oxygenators contribute to the pool's welfare in other ways. Just by being there, they offer enough competition for sunlight and food to keep microscopic vegetable organisms from multiplying too rapidly. It is these tiny suspended vegetable organisms, in overabundance, that turn pool water a murky, unattractive green.

Foliage of tile submerged plants also serves, to an extent, as a bed

to receive the spawn of goldfish and provides a protective cover in which baby fish hide.