Build the Perfect Goldfish Pond

The idea of a crystal clear goldfish pond, with birds and butterflies flitting about, and the gentle, rhythmic, therapeutic sound of babbling water soothing your mood can be very tempting. The idea of a green, smelly hole full of algae, dead leaves and dead goldfish can be equally off-putting.

So getting it right is important. The following checklist will enable you to make the correct decisions before digging a hole and filling it with water and goldfish.


The goldfish pond needs to be in an area that gets about 6 hours of direct sunlight per day. As there may also be the need for pumps, filters and possibly UV treatment mechanisms to control algal growth, it will need to be positioned where an electrical supply can be installed. Leaves can poison goldfish, and tree roots can easily pierce any pond lining, so keep the pond away from trees as much as possible. Finally, try to site the pond in a flat area of ground.


Goldfish pond liners come in three main types: sheet, pre-formed plastic and concrete. Using a sheet offers the most flexibility in terms of shape but they are more easily damaged by rocks and roots. Preformed plastic liners offer convenience and are more durable than sheeting, but there is obviously a limited number of designs. Concrete lining is the most sturdy and long lasting, but requires a lot of work if the pond ever needs to be removed.

If using a sheet, the size required is calculated as follows: length = maximum length of the pool + twice the maximum depth, width = maximum width of the pool + twice the maximum depth. Then add a couple of feet both ways for the overlap round the edge of the pond.


The most popular shape for a goldfish pond is natural looking rounded curves, but there is nothing wrong with square, rectangular, circular or polygonal. Each of these can look visually stunning in a well landscaped garden.

The body of the pond should have at least one shelf for marginal plants, and the sides should be sloped to prevent ice getting stuck deep in the pond in winter time.


The most common mistake made at the first attempt at a goldfish pond is making it too small. Larger ponds are easier to maintain because they form self-regulating ecosystems that in some cases do not need any intervention e.g. filters and pumps. The depth doesn’t need to be any more than 2 or 3 feet in most climates, but in parts of the world where it can get very cold, extra depth will be required.


The number of fish a pond can sustain is dependant on a wide range of conditions. The amount of water is the most obvious, but filtration, aeration and the size of the fish must also be taken into account. A general rule is 6 inches of fish length per 350 litres of water. Bear in mind that natural lakes and rivers do not support large densities of fish like would be seen in an aquarium.


The plants that are best for a goldfish pond are fairly dependent on the part of the world the pond is in. The best place to find out about pond plants is a local garden centre. Anacharis and water lily are usually recommended.

Following these guidelines will help make sure a goldfish pond is an attractive garden feature, and maintaining it does not cause endless headaches.

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