THE POND IS IN…let the fun begin


let the fun begin!

Your pond is in and the dust has settled; here’s how to prepare and plan for the new additions to the family.

Everything else is done and you are busy filling your pond with water, but before you actually bring home some koi or even goldfish, take some time to brush up on the basics. I have heard sad tales of excited pond owners adding too many fish too soon, and being greeted by less than half of them the next morning, the rest having succumbed to toxic wastes in the water. You can avoid the common mistakes and make your fish-keeping pleasant and fulfilling by following the tips and advice that seasoned koi-keepers willingly share.

Preparing the Water

Once the pond is full, the pH of the water must be tested. You can buy a test kit or take a sample of water to your nearest koi store and ask them to test it for you. The pH must be between 7.2 and 8.5. Water in different areas has slightly different pH levels – if you find you have very alkaline water then you can add some acid to bring down the pH to an acceptable level. If the water is very acidic then you can add bicarbonate of soda at 1 cup per 4 000 litres of water. Keep adding bicarb until the pH reaches an acceptable level.


Tap water contains chlorine and chloramines, which are harmful to all fish. You can sort out this potential problem within minutes by neutralising the chlorine and chloramines with a de-chlorinator. Most de-chlorinating products treat both chlorine as well as chloramines, and getting rid of the chloramines normally just requires a double dose. Simply check the product labels before you buy.

Filtration and aeration

Make sure you purchase a filter that is big enough to provide adequate filtration for the volume of water your pond will hold as well the number of fish you plan to keep. You will avoid frustration and disappointment if you remember that biological filters are not able to work instantly – it takes six to eight weeks for the filter to mature and work effectively. Ammonia and nitrites, which are produced by metabolizing fish and organic matter, are toxic to fish and thus must be controlled, which is why you need a bio-filter. Once established, the bacteria in the filter convert the ammonia to nitrite and then into nitrate, which is less toxic to fish. The filter must run continually because the bacteria die if they are deprived of the flow of oxygen-rich water. In addition to this, the water must also be constantly aerated. This benefits both the bacteria and the fish and can be achieved with air pumps, venturis and features such as the water chute that was included in the pond installation elsewhere in this issue. Even when the filter is working effectively you will need to change a percentage of the pond water on a regular basis. It is best to do small water changes more often (as opposed to leaving it too long and then having to do a major change), and there are test kits available that indicate when it is necessary.

Pond maintenance

It is best to clean the filter foams every week to keep them effective and to prevent the filter from clogging up (as that would prevent the water from flowing back to the pond). The bio-balls or other media at the bottom of the filter do not need to be cleaned that often – every few months will do. The media is where the good bacteria become established and after cleaning it you have to give the bacteria time to re-grow. In smaller ponds, including most of the pre-formed fibreglass ponds, there are no bottom drains and therefore organic and inorganic debris accumulates on the floor of the pond. Siphoning it off from time-to-time cleans the pond and removes the organic waste that would otherwise contaminate the water as it decomposes.

Introducing fish

Once you have seen to the items already discussed you are ready to start with the most rewarding part: introducing the fish. With smaller ponds one begins by introducing between two to four fish for the first two weeks, thereafter bringing in more. The two most important factors in this process are to let the fish become acclimatized to the water in your pond by following the steps set out below, and avoiding spilling any of the water from the koi bag into your pond.

Step 1

The koi shop will place your fish in a plastic bag with sufficient water to keep them comfortable. As soon as you arrive home place the sealed bag in the pond and let it float around, allowing the temperature of the water in the bag to equalize with that of the pond water.

Step 2

After 20 minutes have elapsed open the bag, estimate how much water it contains and add an amount equivalent to 30% from the pond, then retie the elastic band. The pH level in a pond will often be higher than the pH level in the bag and this process helps cushion the shock the fish would otherwise experience if they were put straight into the pond.

Step 3

Put the bag back in the pond and allow it to float around for another 10 minutes.

Step 4

Remove the bag, untie it and take the koi out of the bag with a sock net or your hands. Discard the bag and the old water – do not add it to the pond as it may contain high levels of ammonia.

Step 5

Keep a close eye on your new fish. Koi tend to jump a lot when they are first placed in a new pond, so you may want to place some shade cloth or netting over the pond for the first night or while you are unable to watch them, to prevent them landing outside of the pond.

Step 6

Enjoy interacting with your fish and remember: if you care for them meticulously these new family members may even outlive you. In Japan, where keepers are fanatical about their fish, the average lifespan of a koi is 70 years, but they can live for centuries. {

2010 Koi Shows

24 and 25 July: Lake Eland Game Reserve KwaZulu-Natal Koi Show, at Gateway Theatre of Shopping (Parkade C) in Umhlanga.

14 and 15 August: Eastern Cape show, venue to be advised.

28 and 29 August: Western Cape show, venue to be advised.

Article written by Angela Beckx of Koi @ Jungle. Contact Angela on 031 209 8781 or visit: Koi @ Jungle also stocks swimming pool products and equipment.

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