How to Build a Small Pond for Fish
This article is for small ponds containing koi and goldfish.
DIY Fish Pond:
It’s not too hard to build a fish pond, especially a small pond.
In-ground ponds:
Dig a hole.
- Place underlayment in the hole. (Some skip this important step. The underlayment will protect your liner from whatever is in the ground: sticks, tiny rocks, broken glass. Remember, once filled, there will be constant pressure on your liner, pushing it into the earth below it. See pic below.
- Place the liner on top of the underlayment. It is really not a good idea to go cheap on liner and get the thin stuff. Digging a hole, placing stones (more later), leveling—these are simple in concept but take time. You don’t want to have to tear apart a leaky pond and have to build a new one all over again.
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Placing Underlayment
Before purchasing supplies for your pond, decide whether you want an in-ground or above ground pond. Also consider your area’s climate. This will help determine how deep your pond should be to support aquatic life in the winter.
A Formal Pond
Above-ground ponds:
The easiest and often least expensive way to create an above-ground pond is by converting an old spa or above-ground pool you no longer use into a pond. It is trickier to make an above-ground pond from scratch. It will need walls, which can be concrete or a weatherproof wood. You still need a liner unless you are installing a preformed pond made of plastics or you pour concrete walls that you are certain will not crack or leak down the line. It is hard to be sure of this without a liner.
The depth of your pond should be at least three feet in the deepest area for both in-ground and above-ground ponds. It’s optimal to have spots that are four feet deep. Your fish will need space to move and shallow ponds can freeze over in winter and get too hot in summer. Also, birds and other predators will eat your fish if the pond is too shallow.
As a general rule, circular ponds will circulate water better than square ponds.
Where to Dig or Place Your Pond:
- For in-ground ponds, you must first make sure you are not digging where there are buried cables. You can call 811 and have a utilities worker to let you know where utility lines might be buried on your property.
- Avoid digging near trees or their roots could puncture your liner and leaves could fall into the pond, dirtying it as decomposition takes place.
- You also don’t want to dig on a slope. Debris, pesticides, and other chemicals will runoff into the pond, causing considerable damage to the pond ecosystem.
- Regardless if it is above or in-ground, do not place a pond under trees.
- You need to make sure your pond is placed near an outlet. It should have a GFCI for safety. You will need to have a pump at minimum, and you might also want to add lights or other equipment.
- Make sure there is a nearby water source. There will be evaporation.
- Plants require four to six hours of full sun each day to thrive.
- Fish need some shade during the day, though this can be created with water plants.
Circulating the Water (How to Build a Fish Pond)
The simplest kind of pump to use is a submersible water pump. If your pond has fish, the water should recirculate once per hour. For example, a 1200-gallon pond requires a 1200 gallon her hour pump. To calculate pond volume, use this simple formula:
Average length x Average width x Average depth x 7.48 = Total gallons
Edging Your Pond:
`1. For above-ground ponds, the top edging of the pond will be controlled by what material your sides are made of. You might have wood edging at top, concrete, stone, or no edging.
- For in-ground ponds, typically stones are arranged on top of the liner around the ponds. Flagstone typically is the easiest way to edge your pond and protect your liner but sometimes you can use whatever stones are already on your property.
Adding a Waterfall
Some people prefer to add small pond fountains to small ponds, but usually a waterfall is prettier. Believe it or not, adding a waterfall is pretty easy, easier than building the pond. You can form a mound with the dirt you dug up to create the pond. You will need to carve out a flow way. You must use underlayment and liner on the flow way. Make sure all the splashing water curves into this flow way and over the lip of the waterfall. Waterfall lips can be made easily with flagstone. Rule of thumb: For ever inch of width of spillway, you will need to pump 100 gallons an hour. For more splash and action. double that. The higher the drop, the more sound.
Pond with waterfall
Have fun!