Fish farming holds great promise for the problem of diminishing world protein resources. Raising fish in ecologically balanced ponds or pools on a commercial or homestead scale is becoming a more common practice in America for many reasons.

There are no rules to follow in artistic aquarium planting except the general ones of proportion which apply to all garden compositions, indoors or outdoors. Mass the tall plants at the back and corners for background effects. Bushy plants should be placed at the side or in the corners and specimen plantings can be made of different varieties. In a large aquarium of more than five gallons capacity, nothing is better than Vallisneria. Commonly called eel- grass, it is a tall, thin plant with ribbonlike strands which swing to sight and left below the water surface. It is used in clumps or as a solid mass across the back of the tank.

There are two types of pond construction the dug pond formed by digging a sunken shape out of the earth, and the levee pond made by natural levees or by mechanically digging out a level pond bottom. Levee ponds allow for drainage naturally since they are higher than ground level.

When the pond is fully constructed and the clear water allowed to stand for a week or two, it is time for fish body weight per day; with kitchen wastes, percent of body weight. This formula is designed to produce a 3 percent weight gain per day.

The prime location for a fish pond is a low, wet area immune to natural flooding and with soil high in clay content. A Soil Conservation Service agent can evaluate a potential pond site upon request. In general, the land area should be flat with gradual slopes for drainage or spillover.

In starting his aquarium the beginner should keep in mind the following four basic functions that plant life performs: (1)Its ability, under the influence of light, to develop free oxygen and to absorb carbon dioxide. This function is absolutely vital to the animal life in the aquarium. (2) Absorption through its underwater roots and leaves of the fecal matter excreted by the animal life. (3) Helping keep the water clear by competing successfully for food with microscopic vegetal organisms. Salvinia, duckweed and Azolla are excellent for this purpose.

Aquaculture is a science open to the future. Experimenters like Dr. William McLarney and the New Alchemy Institute in Woods Hole, Massachusetts, continue to compile data on backyard fish farming, working with heated geodesic-dome-covered ponds housing tilapia and other exotic species of fish.

Others, such as Rodale Resources in Emmaus, Pennsylvania, and the Institute of Local Self- Reliance in Washington, D.C., are innovating in the areas of water filtration, fish feeding and harvesting techniques.