Steps to introduce fish into your new Koi pond

After much time, money and effort spent building a new pond for your Koi keeping hobby, the next steps which is one of the most exciting. It is to introduce the fishes into the pond. Don’t make the mistake of buying and adding expensive and prized fish into your newly built pond.

There are some best practices to consider here.

The biological filter of your new pond will require time to cultivate the bacteria and function properly.  Bacteria cannot grow unless there is fish waste or ammonia to feed the bacteria.  A good practice is to add some cheap “sacrificial” fish to start the nitrogen cycle. Many beginning Koi keepers suffered the “New Pond Syndrome” where many fish got sick and died in the new pond even though they had build an great pond with excellent filter system, aeration and layout.

Start with a few cheap or pond quality koi in the new pond.

Here are the steps I would suggest:
1. Introduce fish gradually, starting with a few, say 3 to 4.

Buy “cheap” fish or Pond quality fish. Better still, start with Ogons or Chagoi  as these are relatively inexpensive as compared to Showa, Sanke or Kohaku or Shiro Utsuri.

Many Chagoi in this pond with crystal clear water.

It is good to have one Chagoi in your pond as Chagoi are more hardly and also tend to less fearful when it comes to feedings. Chagoi will tend to calm the rest of the Koi in your new pond. One-year old Ogons or Chagoi cost about $5 to $10 locally in Singapore. 

2. Monitor and test your water regularly.

3. Monitor your Koi and detect sudden behaviour changes. Do not overfeed (a common error for the new pondkeeper). Overfeeding fishes create extra waste which the immature biological filter may not be able to handle.

4. Increase the population slowly, allowing the biological filter to adjust. Normally, this will take about 2 months. Sudden increase in amount of fish, leading to sudden increase in amount of fish waste to process will lead to water quality problems such as spike in nitrite and nitrate levels. The symptoms are sick Koi and green water or excessive algae.

Take time to appreciate the latest addition to your Koi collection before the itch to buy one more new Koi comes. In any case, if you are keeping high-grade Koi, adding one Koi at a time slowly over a longer period of time is easier on your pocket.

5. Let your pond mature. Once the pond stabilises and you gain confidence in your Koi keeping and water maintenance skills, then go splurge on your expensive prized Koi!