Designing & Planning a Koi Pond

Position, Type and Shape

So now that you’ve all fired up to create a koi pond sanctuary in your home, lets begin with the important step of designing and planning for your pond. Koi’s need space, and quite a bit of them. Many hobbyist would have started with a small (or not so small) shallow ornamental pond decorated with plants, which looks nice, but are totally unsuitable for Kois. You need at least 4 foot (6 is better) depth for crystal clear water and a good-size filteration system for a successful koi pond. There are options for smaller and good set ups, so its important that you view as many ponds as you can, either through a local club (feedback and ideas from other members are always good), books in the library which shows photographs of various ponds as well as online resources. 

Three aspects of a koi pond correlate with one another, position of the pond, the size and shape. These inevitably depend on one another so you need to weigh out the options for all three.

Position of pond

Perhaps you want to have your pond near the lounge or dining room patio door so that you can just simple stroll out and observe your koi swimming around, or you may decide to put it further up the garden. Regardless of where you decide to put your pond, there are just about a few tips on where you should NOT put the pond:

Keep the pond away from large trees – This is because the roots of species such as Weeping Willows or bamboo will seek out water, penetrate through the later of pond liners and damage your pond.

Keep pond away from poisonous plants – species such as Euphorbia, Yew, and Laburnum are some of the poisonous type of plants you should keep away from your pond. Plants like Silver Birch are also in this category, so make sure that you get rid of the leaves and catkins if you have this species of plant in the vicinity

Keeping the pond clean – Some plants, like the privet hedges, are often planted to keep the wind off the water surface of the pond. However, on a windy day in Autumn a lot of leaves will fall into the pond.


      If you have children in the house, then it is obvious that you will have to be wary when children (or grandchildren) wander into the garden. Children can be persistent with a pond, and even more so with a couple of kois swimming around and piqueing their interest.

      In conditions like heavy rain, and a poorly built pond, be aware that there is the danger of the sides of the pond collapsing and undermining the foundations of the house if you build it too close to the house.

      Seek professional advice from an architect or an experienced builder if you want to do this. You will need to adhere to local regulations and professional builders or swimming pool builders will use shuttering when digging as deep as this. This is also true when there is always the danger of a cave in especially when digging out trenches.

      Always make sure than you don’t work alone and that there is always another person above ground who can get assistance in case of an accident.

      Type & Shape

      With all your research into the type of pond that you like, you will now decide what shape and type you desire. Will it be a formal or informal pond?

      Will your pond be the centre point of your garden and landscape? Or do ou prefer a pond built to hold first and make general maintenance / access as easy as possible?

      You will need to build a pond that suits your personal taste.

      Will you build a pond that is level with the ground? This will give merge the pone with the landscape of the garden. Having it raised up by a couple of feet allows you to sit on the wall while observing the fish. You can have ponds of any shape, but ponds with sharp curves should be avoided especially if you use a butyl liner.

      Size of Pond

      Bigger is always not better.

      There are a couple of things that will factor against the decision to building a huge pond.

      1. You will need to provide more maintenance and personal effort should you decide to keep your fish in a large pond. Bear in mind that a large pond with more fish will pose difficulties for you when you have to catch, check and treat each fish should the need arises. You will also need more effort in making sure that the pond is in tip-top condition, as this is something you definitely CANNOT forego when wanting to keep a successful koi pond.

      2. Cost is also another factor. This not only includes the initial cost of building the pond and requiring a larger filter system, but also of running/maintenance costs. The more volume of water in your pond, the higher the cost of the below items:

          Electricity to run larger pumps
          Replacement of pumps cost
          Chemicals (salt for Spring & Autumn treatments etc) that you will need to carry out periodically

            Depth of pond

            The pond should generally be about 6 feet deep. However if you’re building a pond that is much smaller, then a depth of about 4 feet (plus 1 feet for bottom drains) would just about right. You will need to decide upon this based on the weather condition of your area. Typically a pond that is too shallow will not offer comfort to your kois especially during the winter months or over a really hot day.