Backyard fish ponds add visual interest and aesthetic value so designers suggest picking a spot for one close to a patio or entertainment area, making sure it is not too far to the back of the property.

"You want to put it where you're going to get the most enjoyment out of it," said Stacie Zelenka of Pondscapes in Thurmont, Md. "Incorporate it into your outdoor living space."

A site close to other living spaces also makes it easier to install electricity for filtration and a pump for a waterfall or fountain, one of the highlights of a pond.

"The best thing about having a pond is that the moving water is so therapeutic and relaxing," Zelenka said. "You come home from a hard day and it releases all the stress of the day in your own little sanctuary."

RESOURCES">Pondscapes, Inc.">Lilypons Water Gardens

Keep in mind that deciduous trees will drop leaves in the water, but for homeowners who do not mind scooping some out in the fall, a small nearby tree, like a Japanese maple, can be a nice design feature.

Ponds can be located in a shady yard but should not be completely shaded or under a tree. "Most aquatic plants prefer to have about four to six hours of direct sunlight in order to get maximum bloom," Zelenka said.

Jon Sander of">Lilypons Water Gardens in Adamstown, Md., said some pond plants have both an aesthetic and a functional role. Submerged grasses oxygenate the water and serve as a natural filter, and also compete with algae for nutrients. Water lilies provide blooms and block the sun.

"You want 60 percent to 70 percent of the water surface covered by some kind of aquatic plant," he said. "You want the sunlight blocked. If you have nothing but water, you'll have an algae problem."

Flowering aquatic plants should be fertilized for maximum blooming. While some are hardy and come back every year or can be easily wintered indoors, tropical lilies, which are the most colorful and long-blooming, are trickier and will likely need to be treated like annuals and replaced each year.

Fish in a backyard pond can either be goldfish, which come in many varieties, or koi, which are large, colorful carp.

Sander said homeowners should decide if they are more interested in plants or koi before they start construction.

"There's a difference between a water garden and a koi pond," he said. "Serious koi enthusiasts stick to raising koi." Koi tend to dig, disrupting plants and moving rocks, while goldfish are much friendlier in a water garden environment.

Goldfish will multiply, but even in the city, herons can feast on the fish if they do not have enough hiding places. If a pond gets overcrowded do not dump fish in a natural body of water because it is illegal and bad for the environment, Sander said.

Fish that outgrow a pond can be brought to Lilypons' retirement pond, where some people come back to visit year after year.