How to inherit a pond, fish and koi in a house move.

A surprising number of people who own a pond were introduced to water gardening by accident. Their foray into the outdoor aquatic world arising as a result of a house move, having a pond fall into their lives.

Little did they realise that by buying that house with ‘well-proportioned gardens front and rear which boast a mature ornamental pond’ would prove to be their gateway into pond keeping.

These things don’t just happen to other people – it could happen to you. If it does, what are the first steps you should take?

Fill it in?

Filling the pond in is an option but may well prove to be a mammoth task possibly taking many hours of hard labour. This also assumes that when the pond was originally excavated that the soil was stockpiled next to the pond to form a raised rockery. If the spoil from the original dig is not there then where will you get the soil to fill in the hole? How big are the pieces of stone on the rockery and where can they be moved to?

Once a pond has been filled in, hundreds of pounds of investment and value will have been lost, taking many hundreds of pounds to recover the pond should you later have second thoughts.

Why keep the pond?

A pond can form the focal point of a garden offering many practical and aesthetic benefits to your garden. A living, moving landscape whose character will evolve to reflect the seasons. Attracting wildlife including varieties of interesting insects such as dragon flies, damsel flies and pond skaters as well as frogs, toads and even newts.

Inheriting a pond should not limit the scope to your ideas, but should act as a good basis from which to plan, be it a natural pond, a garden fish pond or a specialist koi pond, each with their own appeal.

Of course, when considering the benefits of a pond, we must be realistic and also recognise the costs. Budgets are likely to be at their tightest when moving house, with a pond that may need some money spending on it appearing on the list well below any new carpets and a fitted kitchen. If this is the case, and the pond is in need of renovation with no fish apparently in residence, it may be worthwhile putting your pond into ‘dry dock’ while you formulate your plans for the pond when budget allows. At least by cleaning out the pond you should gain a greater appreciation of the size of the your pond and the scale of your task.

This will also set your mind thinking about the options, gleaning ideas from TV, neighbours, aquatic outlets, books and magazines. Is it to be a wildlife pond, a fish pond or a koi pond? Your decision will determine how much work would be required and be reflected in your budget. The choice is yours.

The First steps. Assessing your inheritance.

Carrying out a pond assessment will help you to determine whether the pond you have inherited is really worth persevering with or whether it would need a complete rebuild to give you years of enjoyment.

Checklist for a Pond Assessment.

A pond assessment is a method you can use to answer 3 vital questions:

A. What state is the pond in now? B. How does it compare with how I want it to look? C. What is the scale and budget of a job of that size?

These are best answered by looking at the following:

1. Pond structure – Liner, preformed, or concrete.

First impressions at this early stage may not count for a lot. Inherited ponds are rarely in a presentable state often being neglected during the period the house has been up for sale.

A good clue as to the integrity of the pond’s membrane is the water level. If the water level has dropped, it maybe through a leak or evaporation, and can be verified by filling up the pond and monitoring the level for a day or so. If there is an old and stubborn tide mark at the current level then it is more likely to be leaky above this level.

The pond’s structure and water holding capability is of paramount importance and should be assessed for its life expectancy. Who knows, you may be living in this house for many more years to come.

1. Liner Pond. Things to look out for.

Is the pond liner intact? Some liners can become bleached and brittle after years of exposure to the sun. Confirm that there is still a good degree of flexibility in exposed areas of the liner, around rockwork and edging as a brittle liner will indicate that it may be coming to the end of its life. In addition, liner ponds can often suffer from slight subsidence and movement of earth beneath the liner. Shelves may slump and begin to sag or pond edging may appear as though it might slip into the pond. Relining a pond would mean that you could rectify these problems.

2. Preformed pond.

As long as you are able to confirm that it still holds a pond full of water, there is very little that can go wrong with a preformed pond. They prove to be very durable and UV resistant.

3. Concrete.

Concrete ponds can prove to be as reliable as preformed fibreglass ponds. However, build qualities differ and they can start to flake or crack after years of frost and ice attack. If the exposed pond edging appears to be sound with no signs of flaking, then leave well alone. A good concrete pond if well looked after can last for generations.


Being new to fish, there are a number of useful guidelines to follow to make sure any inherited fish remain healthy. You may find the pond in such an overgrown and silty state that you’d find it difficult to believe that it could support fish life. Ornamental pond fish, particularly goldfish and shubunkins are very hardy and adaptable fish, living in and feeding off the organic debris in a pond and can be found thriving in the most apparently inhospitable silt. However, fish will suffer should you disturb the pond water and stir up silt and the smelly sludge from the bottom. If you are aware of there being any fish in your new pond, leave the pond well alone until you have decided to progress with your aquatic DIY project. If you have decided to drain down, then you would be stuck with finding a suitable pond for the fish. A water barrel filled with tap water is not the answer.

Pond Equipment.

The presence of existing pond equipment (pump and filter) may well help you decide whether your new pond is going to be a still, back-to-nature wildlife pond or a recirculating fish pond.

Is there a pump and filter or does the pond resemble a crime scene with pieces of trailing flex or junction boxes with no equipment attached? Is there an obvious flattened weed-free position next to the pond where the filter used to be or is it still there? Is there a cable leading down into the murky depths signifying the presence of a submersible pond pump (or has that gone too along with the shed which you also though was included in the sale?).

If a pump is present, then pull it out as gently as possible and see if it is connected to anything. You may find a flexible hose leading up to where and external filter is (or was) and even perhaps another outlet connected to a fountain or ornament. It is very difficult by inspecting a pump’s external appearance to assess the condition of the pump. A simple service that includes the removal and strip down of the pre-filter (if it has one) and to check that the impellor spins freely should give you some clues as to its condition.

If the vendors have left you the filter as well then it is a fair bet that it will need a good clean out. Before tipping its grubby contents out on to the lawn, dismantle it piece by piece and memorise the order in which the media is set, even down to the order in which the coloured layers of foam go. Coarse at the top, fine on the bottom.

If the pond filter is not running, then you can simply give the filter a thorough clean under tap water. If however, the pond and filter are currently active, clean the filter out with pond water which is not as harsh on the bacteria as tap water.


The most effective way of assessing the variety of plants in your new pond is by draining it down, especially if there is a centre-piece lily in the deepest part.

Plants in a mature pond can often benefit from re-potting as vigorous growers such as water iris, reeds and especially water lilies can soon burst out of the strongest of planting baskets.

There is also the strong likelihood that the water will be thick with submerged oxygenating plants having spread through the water. These too should be removed, the best selected, re-bunched and re-potted in a newly filled basket.

If it is winter time, then foliage will have died back, making the task of tidying and re-potting much easier. But be careful not to discard any non-descript clumps as they may burst forth with luscious new growth in the spring. If in doubt, hold onto it until the spring.

Rockwork, paving and edging.

Tastes rarely coincide, you just need to take a look at the dcor of your new house. The same can be true for the way in which a pond is styled or finished. When considering what to do with the new pond, consider the pond and its finishing touches as a whole. If your predecessor has used broken concrete flagstones for edging and a pre-cast set of plastic waterfalls and you want to give it a more natural ‘slice of the Lake District’ effect, then flags and plastic waterfalls will have to go. A ton or so of sand stone slabs will need to be ordered for the new edging and waterfall, to be made from stepped natural stone.

Having assessed the assets and liabilities of your recent inheritance you should now have a clearer picture as to what you want from your pond. You should also have an idea of any costs involved to make the necessary changes. Perhaps the final decision is whether you start the project now or wait until your house’s interior is in order.

Kill blanketweed and string algae.