A reliable Koi pond.

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A good start is half the work.

Written by Hugo J. Smal

Koi garden
It’s nice to see Koi in a proper garden.

There is a lot to discuss how best to build a koi pond. Every advanced koi lover has his thoughts on this (which, incidentally, are quickly elevated to dogmas) and tricks that are often worth taking over. Visiting many koi ponds is therefore recommended. Most enthusiasts are proud of their pond and will be happy to have it viewed. Save all information obtained and choose your starting points. Remember that every pond is different and will develop differently. I will therefore only give preconditions and no blueprint. But with this, we help you to get a reliable Koi pond.

To my knowledge, a definition of the good koi pond has never been given. I attempt: a good koi pond is a water feature in which large carp can live in a safe, healthy and happy way. The beauty of the design is of secondary importance. After all, the carp do not care whether they swim in a golden or a bronze pond.
Safety, health and happiness are the preconditions. It is very important to realize that just like a filter, a pond must mature. Building a new, even better pond every year may be fun for construction enthusiasts. But it is downright bad for the fish. They prefer to stay in their familiar pond all their lives. That is why it is necessary to think and plan everything well in advance. It is even better to postpone the construction of the pond for a year and to save more money than not to start well prepared. Haste makes waste! This also applies to your Watergarden.

A reliable koi pond means safety!

Although the three preconditions overlap, everything also has to do with water quality, I still want to treat them separately. By safety, I mean protection against external hazards. Herons, for example, love a beautifully coloured snack and will not remove a large carp from the pond, but will damage it considerably. So take measures against this. Sharp objects (an iron hose clamp, for example) can also cause damage. So always choose ti-reps when something needs to be secured.

Even if leakage occurs, the fish can be endangered. They simply don’t do it on dry land. That is why it is necessary to always choose the best materials. Cheap alternatives always turn out to be the wrong purchase afterwards.

This pond has waterfalls, decorative rock edges, equipment enclosures and decorative features shown along with the diagram of the filtration and water treatment system. (From The Atlas of garden ponds, TFH Publications.)

Foil is a good example of this. Some people believe that a good and safe pond can be built with agricultural liner (sometimes they use five layers). Forget it. Even the PVC film specially made for the pond cannot be trusted.
A koi pond in which expensive fish swim around should be constructed with at least rubber-based liner. It last a very long (unlimited) period, have no adverse effects from the UV rays of the sun and also throughputs and bottom drains are easy to realize. Where a heron sometimes pierces PVC, this material has high impact resistance.

Leaks can also occur in filter systems. That is why it is important to place or secure the pump in such a way that the pond can never be completely emptied and a layer of water of at least 30 centimetres is always left behind. Exaggerated warning? You will have to give those hobbyists a pint, who after a well deserved holiday or even a short night’s rest, finding their beloved fish in a dry tank. It may also be an exaggeration to warn against unsafe power consumption. But here again… you will have to give them a pint.


Good start
More Koi info

It is also important to point out the dangers that some garden plants can pose to fish. The leaves of Yellow rocket (Laburnum anagyroides) and willows, for example, contain tannic acid and can cause paralysis in the fish. So with every garden plant, you have to ask yourself whether it should be allowed near the pond.

Healthy carp in a reliable koi pond.

The most important thing here is the water quality. This is kept up to date with a filter that is marketed today in all shapes and sizes. Good information by a koi specialist or an experienced hobbyist is indispensable when purchasing a system.

koi filter
This thank uses roll filters and activated carbon ribbon filters to produce finely balanced water for a rearing pond.
1) Recirculating tank
2) Recirculating tank filter-fast flow horizontal bars and filters.
3) Two jets pumped from the bottom of the recirculating tank.
4) Valve
5) Recirculating tank drains
6) Fibrous filter material 500 mm thick and chamber
7 Baffle tank
8) Baffle tank drain
9) Fibrous filter-250 mm thick
10) New water jets from pump (#14)
11) Settling tank
12) New water source
13) Settling drain tank
14) New water pump
15) Water from the bottom of the pond
16) Water from drain no. 5 and 8
17) Water from settling tank
18) Rearing pond
19) Rectifying plates and drains in pond floor, and 75 mm calibre pipes
20) Overflow from pond to draining the tank
21) Recirculating pump from the endless tank
22) 100 mm calibre pipes from the recirculating pump from recirculating tank and rearing pond.
(From The Atlas of garden ponds, TFH Publications.)

Here I will list the requirements that a good filter must meet. First of all, a compartment in which bulky waste can settle is of great importance. This dirt must simply be removed with a drain. Subsequently, a compartment with brushes that also collects coarse dirt will considerably reduce the pressure on the compartments with a substrate. In these latter compartments, ammonia and nitrite are converted into nitrate. This is why I have called a filter a “plant manure machine”.

Nitrate is food!

Nitrate is the nutrient for floating algae and is in the filter produced on a large scale. This is why many koi ponds struggle with green water. You can, of course, burn the algae to death with a UV lamp, but remember that the nutrients remain in the water. Alternatives to the UV lamp are a swamp pond or regular water changes.

Plants in the marsh pond are a direct food competitor for the floating algae. So remove the nitrate from the water. You do the same while changing water. This does have two disadvantages: tap water has its price tag and is also different from healthy pond water. If you choose the last control method, it is important to make provisions. I did struggle with a garden hose for many years while a fixed pipe should not be difficult to install.

Tip: with the pond water saturated with nitrate, you can very well spray the plants in your garden. I said before: a filter is a plant manure machine.

The aeration of the pond and filter will also greatly improve the water quality and thus the health of your fish. A good aeration pump (and I don’t mean a wimpy aquarium aeration pump here) is good to use. Air stones in every filter compartment (except the sedimentation area) and in the pond are indispensable. It is very important to ensure that water cannot stand still anywhere in the pond or the filter. Here too, standstill means deteriorating, namely in terms of water quality. After all, standing water does not absorb oxygen and becomes dead water.

The four most frequently asked koi pond questions: How big the pond? As big as possible. How deep? As deep as possible. Pond under 1.20 meters…. turn it into a natural pond. How much water? As much as possible. How big the filter content? At least one-third of the pond content or the operation of the filter must be intensified with ingenious techniques. 

Reware that a properly working filter costs at least 1000 USD and the price of a better working filter can be up to 3000 and higher. Cutting back on this is the stupidest thing you can do. 

Nowadays, the long disappearance of the Nishikigoi under the ice is considered to be equivalent to Kamikaze koi keeping. That is why it is important to also take pond heating into account.

Lucky Koi in a reliable koi pond

The staff of the Goyang Koi farm will be proud when the beautiful fishes swimming in your pond are ours. But first things first. We provide basic knowledge on this site. And for the Koreans who want to start a koi pond, we will always be there to help you!

A discussion can be started about whether koi are lucky or not. When we describe happiness as well-being (this besides health)  koi must be happy. Some adjustments to the pond are also required for this. For example, a feeding place where you can easily touch the koi. It will promote the happiness of your fish. This contributes to the luck of both the fish and their caregivers.

A feeding place means a shallow area where the fish can safely go. 

Yes, feeding is quite a spectacle in itself and if it is not done in a safe place it can cause damage. So do not place stones on or near the feeding place. I know someone who regularly puts a mirror on the bottom of the feeding place so that he can check the bellies for damage and parasites without catching the fish. 

Plants in the koi pond will also contribute to the happiness of the fish. “But koi are turning plants around,” you will say, and you are right about that. You just have to say it differently: Koi are fish that like to toss and play among aquatic plants. 

Therefore, do not choose small and delicate plants, but for example yellow iris and reed varieties. So-called mother plants of water lilies are also available from some aquatic plant growers. When these large healthy plants are placed in a tub with clay (cover with coarse gravel) they will grow faster than the fish can eat. Besides, the koi will leave the plants alone if you feed them properly and sufficiently.

A water lily in the koi pond has three advantages: beautiful flowers, shelter from the sun and heron and the lily also take nutrients from the pond.

Playing koi in a reliable koi pond.

I recommend that you occasionally put floating plants in the koi pond. You will see that the fish will spend hours on the water lettuce or water hyacinths. It costs something but it gives hours of fun for both the koi and the caretaker. You will experience this even better when you put some food balls on the floating plant.

As for luck, another anecdote: Once a koi dealer called me about a problem. He had bought a large koi that was healthy but was still a bit bored on the bottom of the pond. This is always an attitude in which the alarm bells should ring for you. Naive when I was then, I asked him if the fish in his home pond had a friend, a carp he often swam with. He did and once it was bought and brought into the pond the fish became happy. With this anecdote in mind, I dare to say that both a frequently changing pond (increasingly better mooring) and a strongly changing fish stock will damage the luck of the fish.


Koi enthusiasts are known for their stubbornness. They all have their dogma philosophy when it comes to the construction of the pond and the filter. In terms of construction, the experience is a result of bad planning. After all, you get experience by doing something often! That does not speak to their advantage.

So make an inventory of what you want and how you should approach it. Get your experience through drawing paper and not by backache from many digging. Also, draw in the required water currents so you can see what is happening in the pond. Get advice from experienced hobbyists but make your own plan.

If you are unsure?

Numerous koi specialists around the world can supply you with a ready-made product. They give you a guarantee that your fish will live safely, happily and healthily in your pond. It is a bit more expensive but the price tag will turn out small if you compare it with the luck that your own wonderful Nishikigoi will give you.

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