The best shape for a garden pond depends on the look and feel you want to create.
Geometric shapes such as squares, rectangles and circles tend to be best for formal ponds. Curved or irregular ponds such as kidney shapes are better for more natural looking ponds.
In this article we explore the best shapes for different types of ponds, including those for wildlife, goldfish, and koi ponds.
Formal ponds are designed for flawless perfection, minimalism, and often embody a sense of order. They are often symetrical and have no irregularities to their shape. The best shape for formal ponds tend to be geometric shapes such as circles, squares and rectangles, or combinations of these.
Although less commonly seen in the UK, ponds with more than four equal sides also work extremely well for formal ponds. Examples include hexagonal or octagonal shapes which are more prominent in middle-eastern culture.
Trianglular ponds, and ponds with acute angles, should be avoided as their corners create ‘dead spots’ that restrict the flow of water and have a tendency to accummulate waste and disease.
In complete contrast to formal ponds, natural ponds are designed to blend in with the natural landscape. The best shape for natural looking ponds are gentle curves with irregular shapes.
Ponds in the wild never have straight lines or corners, and are never perfectly round. So be sure to create a design that looks like it has been formed naturally rather than being man-made.
A popular choice is a kidney bean shape but there is great scope for creating bays of different depths, with or without planting, and incorporating natural looking water features such as waterfalls and streams.
When designing a pond it is great to get your creative juices flowing. Often there is no right or wrong. Everyone has their own idea of what their perfect pond should look like. However there are some basic design tips for a healthy pond.
Whatever type of pond you want to build, be sure that water can circulate freely. Avoid convoluted designs with narrow channels or nooks and crannies. Try to keep the corners of formal ponds to 90 degrees or more, and the curving bays of informal ponds nice and wide.
Areas of poor water circulation should be avoided. They tend to accummulate waste and decaying matter that harbours bacterial pathogens that cause disease in fish. They also block free circulation of water to pond filters.
Just as important as the shape of your pond is its depth. As a rule of thumb natural ponds should be at least 0.6 metres, goldfish ponds at least 1m deep, and koi ponds at least 1.3m deep.
Ponds of all shapes can in theory be good for wildlife. However natural gently curving pond shapes and varying depths tend to work best. They allow you to accommodate the planting required to create the habitat that wildlife needs to thrive.
Plants are the number one feature a pond needs to support wildlife. They are the ‘corner stone’ of your entire pond ecosystem. Be sure to include marginal planting shelves in your design, and enough depth for submerged aquatic plants such as water lilies. Plenty of plants reduces your risk of having algae problems. Pond plants draw up free organic matter so that nuisance algae doesn’t get a chance to get going.
In addition to planting, consider adding stones and rocks, and other hard features than provide good cover from predators such as birds. Simple stacks of rocks with crevices and hollows provide excellent habitat for invertebrates, amphibians and small mammals. Rocky water features such as waterfalls and streams are perfect for this. They not only create superb habitat, but also bring great beauty to your pond and keep your water oxygenated.
The best shapes for wildlife ponds therefore tend to be those that accommodate the most planting and features to create really good habitat.
The best shape for a goldfish pond is generally one which helps them to avoid being eaten by herons and other predators. The two dimensional shape of your pond is largely inconsequential to their survival. Of far greater importance is having enough depth and cover.
Herons have long legs for wading and long necks and beaks for taking fish from under the water. Even so, their reach is somewhat limited. By providing enough depth to your pond, goldfish can retreat to the safety of deeper water when they see the sinister shadows of these expert hunters appear on the skyline. We recommend a depth of at least 1m.
It is a good idea to have a steep-sided pond without beaches or shallows on which herons can perch or wade. Otherwise you are simply providing them with the perfect dining table.
Marginal planting shelves are still well worthwhile. Provided they are packed with plants and shelve off steaply, you will make it harder for herons to catch your fish. Water lilies also provide excellent cover. Plants help maintain good water quality and provide a natural larder of food for your fish.
Unless you cover your pond with a net then inevitably some goldfish will be eaten over time. However goldfish breed extremely well and ponds can quickly become heavily stocked. But with a careful design aimed at providing enough depth and cover for your goldfish you should be able to strike a natural balance between predation and breeding.
People often ask what is the best shape for a koi pond. In fact, formal and natural shapes are absolutely fine. The key thing with koi ponds is having enough depth and overall volume for koi to be happy and healthy.
We recommend a depth of at least 1.3m, but ideally around 1.5m. A minimum volume for koi carp should also be at least 15 cubic metres but ideally 20 cubic metres or more. This may seem extremely deep and large but koi carp are large creatures and this is what they require. If you cannot provide this size of pond you should consider stocking smaller fish species.
Unfortunately most aquatics retailers are happy to sell you koi for a pond that is completely inadequate for rearing them. Sadly this unscrupulous kind of practice is commonplace in the ornamental fish industry.
If you need genuine advice on how to build a koi pond, by industry experts who have been designing and building koi ponds for many years, please don’t hesitate to get in touch.