Keeping water healthy, keeps your Koi healthy!

Did you know that about 75% of a fish’s body is water, just like 60% of your body is water?

This means it is even more important to have healthy water for Koi than humans. When you consider that Koi live and breathe in water, you can tell how much of an impact that water quality affects Koi health.

The purpose of our writing this blog post to give you a foundation of the nitrogen cycle in your pond so you can maintain healthy water for your Koi. We will also explain our best product recommendation for keeping your water healthy. Good luck and happy ponding!


Nitrogen Cycle of your Koi Pond Graphic

We created this graphic to show the parts of a pond’s cycle and decomposing plant and animal matter.

To keep water quality safe for Koi, the nitrogen cycle must follow the process shown below:

Understanding the Nitrogen Cycle

  1. Koi eat food and produce waste. The food that Koi do not eat also decompose. Both of these release ammonia. Ammonia is very toxic and dangerous to Koi. An ammonia level of 0 is required.
  2. Nitrosomonas is a nitrifying bacteria. They consume ammonia and convert them to nitrites. However, nitrites are still toxic to Koi. A nitrites level of 0 is required.
  3. We need help of another type of nitrifying bacteria—nitrobacter. Nitrobacter consume nitrites and convert them to nitrate. Nitrate is not toxic to Koi.
  4. Nitrates can be easily removed from the system by a water change, or aquatic plants and algae can consume them.

To keep water healthy for Koi, there are many other topics to understand.

However, understanding your pond’s nitrogen cycle is your essential first step to pond management success.

Your Pond’s Need for Bacteria

In this chart above, you can see the important role of beneficial bacteria. Without these 2 kinds of beneficial bacteria, water will harbor toxic ammonia and nitrite and harm your Koi’s health. Even if the water is clear, the existence of ammonia and nitrite means unhealthy water. To keep ammonia and nitrite levels at 0, it is critical that your pond system always host enough beneficial bacteria.

Other reading: How to make medicated koi food for bacterial infections

Your Pond’s Need for Oxygen

Your pond needs more oxygen than you probably expect. Koi need oxygen, of course; but these beneficial bacteria need it, too. (Bacteria that need oxygen are called aerobic bacteria). On top of that, algae consumes oxygen; and when debris decomposes, oxygen is reduced further.

Recommendations for Koi Pond Owners

If your pond is new, the nitrogen cycle is not established yet. So it is important to seed the pond with beneficial bacteria. If your pond is already established, I still recommend you add the bacteria on a regular basis, around once a week.

Koi eat and produce waste every day. The ecosystem changes every day. To keep everything balanced, I feel it is wise to add beneficial bacteria regularly and maintain the bacteria count consistently.

Niigata water bio balls are one of our top selling items and our customers love it’s ability to help maintain a healthy ecosystem. We always recommend natural biological filters for your pond. You may also consider reading about our custom created koi pond filter.

Niigata Water Bio

There are many beneficial bacteria products on the market. Any of them will do the job, but let me introduce my favorite.

Niigata Water Bio is our favorite on the farm for several reasons:

  • First of all, this Japan-made product contains about 20 billion beneficial bacteria and their food in each small tablet. So as soon as it is dropped in your pond and dissolved, they can multiply themselves quickly.
  • Secondly, it may surprise you to know that the bacteria in Niigata Water Bio can live in cold water as low as 41F. So it works great even at the beginning of spring and fall when Koi are slow-moving and have low health immunity.
  • Lastly, this product has been very popular in Japan for the last few decades since around 1988—meaning it works.

If you are looking to improve the biological filter and nitrogen cycle in your pond, than we highly recommend you try Niigata Water Bio.