PREVENTING NEW POND SYNDROME

Once a pond is built and filled, many a new pond owner runs to the nearest Koi dealer and stock up with a selection of Koi only to find a few days later he has health problems with his fish. During the next few months he may experience what is known as “New Pond Syndrome” as seemingly inexplicable maladies beset his pond from green or turbid water to fish dying. But this is just nature’s way of sorting things out and making sure that all organisms in the pond, from the fish load to the plants and bacterial life establish a balance amongst themselves.

Starting a new Koi pond successfully is more a matter of restraint than anything else. There is absolutely no reason to subject perfectly healthy fish to an environment that will stress and ultimately kill them because a pond owner is careless or in a hurry. And to put in a few sacrificial fish to test the water and see how it goes, is a medieval way of thinking. In fact it could be cruel.

So, what is the correct way to prepare a new pond for fish?

The assumption is you are using city tap water to fill your pond. If you are using any other water it is essential that you assess the suitability of the water for fish by asking other people using the same water or by getting it tested in a lab.

It is wise for new pond owners or the builders to invest in test kits. These test kits need not be expensive, but being able to test for pH, ammonia, and nitrite should be regarded as essential pond owner’s kit. Stocking up with the dipstick type alkalinity and hardness kits will also greatly assist in evaluating the water quality.

Fill up the pond and while doing so take a water sample and record the pH, alkalinity and hardness as a reference. (One can also test the ammonia, nitrite and nitrate levels for future reference). Switch on the pump to oxygenate the water and assist with the dechlorination process. (Town tap water may be chlorinated for human health reasons and it will kill fish.)

You have a new pond. You have filled it and all mechanical systems are running. But remember, it is not ready to put fish in yet.

You may not be one for all this testing, but at least test the pH! A new pond with a pH 9 or higher has killed many a fine specimen of Koi due to the over enthusiasm of ponds owner to have fish in their pond.

Nevertheless, one or two days later test the pH, alkalinity and hardness again. One can now establish the effect the pond has on the water.

What to expect from your new pond water:

Now what do you do with all this information? There is a wealth of information locked up in the behavior of these basic water quality parameters over the first two days of the pond, but it is beyond the scope of this short note. Suffice to say that if any of the above parameters are out of range call for expert advice as to the best cause of action to take. He will need your test results, so have them ready.

But one thing is sure: If the pH is out of range it is serious and the cause of the problem must be established. Do not put in any fish in your pond until this problem is rectified.

Once the basic inorganic water quality is acceptable, it is time turn to the need of the fish you intend stocking up with. The bio filter needs to be “started” or primed and that is a slow process that can take a month in cold conditions. (read more about biological filters) A biological filter is populated by living organisms that oxidizes toxic fish waste (ammonia) to relatively harmless nitrates.

It is important to realize that these organisms depend on the ammonia for their sustenance and a biological filter cannot become populated without “their food”. So running the pond for a week or two, or even a month, in the absence of fish will do nothing for the maturation of the filter. On the other hand, stocking up with too many fish may soon lead to health problems, as the “immature” filter cannot cope with the ammonia load.

So, what can you do?

First option is to put only a few fish in the pond and record the ammonia and nitrite levels at least twice a week. You will notice the ammonia rise, reaching a peak in a few weeks time and dropping down to zero. This indicates that there are sufficient bacteria to cope with the ammonia excreted by the fish. Should, during this time, the ammonia level reach toxic levels (>0.3mg/l) partial water changes should be made to dilute the ammonia to acceptable levels (<0.3mg/l)

But it is not the end yet. Following the ammonia peak will be a nitrite peak that can be just as hazardous for your Koi. So keep an eye on that.

Once you are sure the bio filter is handling the fish load, you are ready to introduce more fish. While yet again keeping an eye on the ammonia and nitrite. What a schlep!

This process can be speeded up by adding some of the bacterial culture preparation found on your Koi dealer’s shelf. But do not rely on it. Testing and taking care of what is happening is still vital because these products do not always react in a predictable manner.

Point is, it is a relative slow process to mature the bio filter by increasing the fish load and you have to keep an eye on it or “new pond syndrome” will come and bite you.

Alternative solution: Dose your pond with an artificial feed for bio filter microbial life (eg BioPrim-A®) Note: this is the feed, not the packaged live bacteria (which you can still add) The dosage is calculated to simulate your ultimate fish load. All you do is monitor the ammonia and nitrite, add a few top-up dosages, and you are ready to introduce your full fish load, and never have to worry again.

Note the following: We did not worry about chlorine, but we exercised restraint.
We did not subject sacrificial fish to torture, but we measured pH
We did not subject our fish collection or ourselves to stress, but properly primed the bio filter.

New Pond Syndrome?
Over the next year your pond will continue to mature as seasons change, you add more fish and your fish grow. When the pond cannot cope with changes in water quality conditions, the fish may become stressed and diseased. This seemingly inexplicable malady that besets new ponds is often termed “new pond syndrome”. If you exercise restraint and maturise your bio filter to handle the full and ultimate fish load before any fish is added, the chances of your Koi collection suffering from any problems, is greatly reduced.

Yes, all that just because you invested in pH, ammonia and nitrite test kits and knew what to do with it.

Only a few fish?
A new pond with new bio filter: You can stock with about 100g of fish per m3 (note volume here) providing you check for high ammonia regularly and nitrite. About 5 Koi of 10cm per cubic meter of water. Or one 25cm fish per 2 m3 (4000 liter) water volume.

A mature pond without external filtration: The stocking rate can be about 200g of fish per m2 of pond surface area. That translates into about 10 Koi of 10cm each per m2.of pond surface. Koi, however, can grow quite fast and at a length of 25cm the pond will only be able to support 1 fish per m2. The “small” collection of “small” Koi will outgrow the limits of their pond, become sick and die. The survivors will probably live a stressful life.

A mature pond with external filtration. Stocking rate is entirely determined by the turnover rate, the size and effectiveness of the bio filter and the availability of oxygen. While very high stocking rates can be achieved, it is recommended for safety reasons that keepers do not stock more than 3kg of fish body mass per m3 (1000 liter) for safety. That translates into one 55 cm fish per m3

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