Backyard Fish Ponds

A backyard fish pond is a simple way to add color and life to your landscape. Although these ponds can run from a small pool to a small lake, a mid-sized fish pond can be completed in an afternoon.

Planning

Style
Ponds can be designed to fit any garden style. A formal garden formal pond is considered to be one with a geometric shape, borders and nearby paths in straight lines, neatly trimmed hedges, and with stone, brick, and ornaments chosen to compliment the house. In an informal garden a pond can take a more natural shape, with gentle curves and irregular shapes to the paths, landscaping borders, and pond itself. Slightly overgrown plants and whimsical ornaments and features can add eye-catching interest.

Pond size
The size of a backyard fish pond depends largely on what type of fish will be living there. A frequent mistake with ponds is to build them too small, which limits the number of fish and plants you can add. In fact, although it may seem that a smaller pond is easier to care for, in reality a larger pond is more stable and easier to maintain. Koi need space, whereas goldfish will do well in a smaller area.

Japanese koi
Koi, unlike goldfish, grow quite large regardless of pond size and should be given no less than 1000 gallons in volume and 10 feet across by 2 feet deep (more if possible). Some part of the pond should be dug to to no less than 3 feet deep to give the koi a place to spend the winter. Koi are also are prone to injury by sharp objects and do not tolerate poor water quality.

Goldfish
Goldfish are much hardier than koi. "Feeder" goldfish can be found cheaply in pet shops and in a backyard fish pond will require approximately one cubic foot of water per inch of body length. Over winter they can be left outdoors (they will freeze completely, but will thaw out in spring) or can be kept in a child's pool in the house. In a favorable environment, goldfish may even breed.

Location

Backyard fish ponds are best located on flat ground in an area where the soil can be easily dug and away from large trees. A waterfall or fountain will also require easy access to electricity.

If the sides of the pond are not absolutely level, the water will seem crooked and the liner will show. Furthermore, rain run-off will flow into the pond carrying fertilizers and other chemicals, as well as organic debris into the pond. Ponds in sandy soils need space for the sides to slope gradually, as sharp slopes will collapse. Partial shade from a nearby tree will help discourage algae growth, but if the tree is too close or too large its roots could puncture the liner and fallen leaves will pollute the pond and possibly kill the fish. Also most pond plants, including water lilies, require at least 4 to 6 hours of sunlight to grow well.

Backyard fish pond material

A fish pond will require a lining, lining padding, and, preferably, a pump. Lining can be as simple as thick plastic or, for more permanent ponds, pre-formed plastic shell. Lining is particularly important in rocky or root-filled soils. While plastic forms are usually thick enough, for a less permanent pond with thinner lining, a padding of old carpet or newspapers is also recommended. A pump is needed to provide oxygen for the fish, although a larger, more stable pond with goldfish rather than koi may not need one.

Finishing the pond

Building the pond edging
For a formal pond, stone or other coping fitted evenly around the edge will add a classic finish. Copingstone can be placed around the edge of the pond and the pond liner folded up behind the stone to slightly above the water level. Stones don't require mortar, but if the stones are too small to be stable or if they'll be walked on mortaring them in place is preferred. Once the stones are in place, back fill with soil to hold the pond liner against the stone.

If your goal is to make your pond blend into the landscape, a less "man-made" edging can be built. One or more layers of stone built up from the shelf under the water level provides a more natural transition and disguises the liner if the water level fluctuates. Another option is a cobblestone beach edging of large stone at the inside of a large shallow shelf and filling the area with gravel and cobbles. Placing water plants here will create a more natural edge with plants partly in and partly out of the water.

Beyond edging, colorful stones, beach glass, or other fishbowl accents placed at the bottom of the pond make eye-catching additions. These will also give the fish a place to hide.

Plants for backyard fish ponds

Aquatic plants should be added as soon as possible, but only after adding a dechlorinator to the pond to remove any chlorine or chloramines or after waiting a few days for the chorine to evaporate. Packaged bacteria can be bought to help start the natural processes in the pond and the pond filter.

Anacharis, an underwater plant that uses nutrients that would otherwise feed the algae, is the most vital plant in the backyard fishpond. Ponds under 25 square feet require one bunch every square foot of pond surface area and ponds 25 to 100 square feet require one bunch for every two square feet of surface area. After this, water lilies and other plants with surface leaves can be added. Plants should cover a little over sixty per cent of the surface area if the pond receives in full sun. In a koi pond a smaller upper pool or plant protectors will be needed to keep the koi from eating the plants.

Adding fish

Add fish a few at a time over several weeks to allow the helpful bacteria to establish in your water garden. As with the plants, water should be chorine-free before fish are added or the chorine could kill them. Before releasing the fish into the pond, put them in a bag of room-temperature water and let the bag float in the pond for an hour or so to let their body temperature adjust. Pouring them into a pond after they've been in a warm house for an hour or so is enough shock to kill them.

Landscaping a backyard fish pond

How you landscape depends on what the pond a focal point of the area is. Is the pond a subtler, hidden element of the garden or is it the main feature?

Choose shrubs and plants that will enhance the water reflection. Arrange them around the pond before you take them out of their pots. Avoid overcrowding the area and leave the plants room to grow. Cattail, bamboo, and water iris should be planted in containers to prevent them from taking over the area. A few nectar rich flowers will attract butterflies and, if they visit your area, hummingbirds. [Visit BLI's other sections for more on attracting butterflies and hummingbirds] Other plants that do well near ponds include water lillies (Nymphaea odorata) , water hyacinth (Eichornia crassipes), cat-tails (Typha latifolia L), Japanese iris (Iris ensata), day lilies (Hemerocallis), forget-me-nots (Myosotis sylvatica), ferns, clover, and small evergreens.

Backyard fish pond maintenance

Try to keep all debris out of the water. The water will evaporate, so fill the pond as needed necessary. The filter should be replaced regularly according to instructions that came with the kit. In the spring and autumn, a small pond can either be emptied and the fish kept in the house, or leaves and other debris can be removed by hand and the fish left in. If you're leaving the fish in, be sure the pond is deep enough to provide a lower level that won't freeze.