Koi Pond Clay

Adding a Little Beneficial Bacteria to Your Water Garden Helps Raise Healthy Koi

If you have your own koi pond and are not making use of any koi clay, you might be unintentionally depriving your koi fish of many health benefits.

Three Clay Pots Beside a Koi Pond
Not Only Can Clay Be Used for Design but It Also Has Nutrients That Koi Wouldn't Obtain From Their Natural Surroundings

But don't feel bad about it! Koi pond clay is not common to the point where every koi fish owner automatically knows about it. I mean, I didn't know what it was for quite a while myself despite having my own koi pond, though if you have done your fair share of research on koi fish, you've likely come across koi clay at least a few times.

In simplest terms, koi clay provides koi fish with many extra goodies that they can't usually get from the natural resources around them. There's quite a bit more to koi clay that I'll get into in the sections below, so read on to learn about the benefits of koi clay and how you can start implementing it!

What Is Koi Clay, and How Does it Benefit Koi Fish?

The two main ways koi clay affects the health of koi fish lie within the improvements it brings to water quality and the extra nutrients that fish need, like proteins, minerals, fats, and carbohydrates. 

Using Koi Clay to Improve Overall Water Quality

Adding koi clay particles to pond water will give the pond more minerals and trace elements that it may be lacking.

This, by extension, improves your koi fish's health, as you are improving the overall quality of the water they are living in.

Many pond owners incorporate their use of koi clay into their pond water changes. They do this because the fresh water is clear of debris, so the clay is used for multiple reasons, but mostly as a supplement to keep koi healthy.

Koi Clay as Supplements for Koi Fish

There are two main types of koi clay: bentonite clay and montmorillonite clay, also called calcium bentonite clay or calcium montmorillonite clay. Adding this clay won’t turn your clear waters into a mud pond; instead, you’re simply giving minerals to your fish to keep them healthy and beautiful by mimicking their natural environment.

Think of this clay as a health supplement, similar to a vitamin you might take. While they won’t be eating this clay, it will still filter through their systems when they take in water.

These clays are smectite clays, which give your koi the essential minerals they need to thrive in an otherwise sterile environment while absorbing any toxins that your fish may have been exposed to.

A Photo of a Clay Pot in the Middle of a Pond with Waterlilies and Lily Pads
Koi Clay has the minerals Your Koi Needs to Thrive in Sterile Environments

Smectite clays usually contain:

  • Calcium carbonate
  • Sodium
  • Potassium
  • Silica
  • Quartz
  • Zeolite

Bentonite clay is actually a form of montmorillonite, but it has extra minerals, including quartz and zeolite.

While acting as a supplement is enough of a reason to give your koi these clays, there are more benefits.

Using koi clay can keep your fish's bones healthy, improve their appetite, prevent birth defects by decreasing toxins, improve anemia, and more. The water quality will be improved, your fish will have boosted immune systems, and their scales may become glossier and more vibrant with their bolstered health.

How Is Koi Clay Used?

Now that we've talked about the various uses and benefits of koi clay, let's go over the two main methods of incorporating clay into a koi pond.

Adding Koi Clay Directly Into Water

Before you get started with this first method, you're obviously going to need some pond clay on hand. I recommend getting some Microbe-Lift, primarily because it's 100% natural.

Once you've gotten your preferred ultimate koi clay, you can mix it up in a container of pond water and pour it directly into the pond.

A Single Maple Leaf on Top of Soil
Mix Your Soil with Pond Clay as it Retains Water and Nutriets

You will need to know how many gallons of water are in your Koi pond. The recommended amount of koi clay per dose is one tablespoon for every 1,000 gallons of water.

Generally, if you multiply the length, width, and average depth of your fish pond to get the cubic feet and multiply the cubic foot number by 7.5, you will get the number of gallons your pond contains.

Adding Koi Clay With Food

This second method is even more straightforward than the first. All you need to do is take some koi food pellets, dampen them just a tad with water, and then use koi clay to cover the pellets.

You can do this a few times a week, preferably three at the maximum initially. After doing it consistently up until the third week, reduce the dosage amount to once or twice per week for best results.

A small plant in the middle of a Koi Pond
You May Add the Pond Clay Directly to the Water or in the Fish Food


There are many health benefits to adding clay to your koi pond. Improving the water quality with supplements provides your fish with an extra boost of essential nutrients that aren't always available in the environment in which they live. Whether you add it directly into the pond water or in the fish food, the beneficial bacteria will go a long way towards the overall health and well being of your koi fish.

Frank Salvatore

In 2015 our family moved into a house south of Denver, Colorado with a  koi pond.  Since that time I've learned to really enjoy the koi fish and the pond. This blog is dedicated to providing helpful hints and information for koi pond hobbyists - as well as those of you who just inherited a koi pond and are thinking NOW WHAT?

About Me

Hey there - I'm Frank Salvatore. In 2015 our family moved into a house south of Denver, Colorado that had a Koi pond. The problem was I knew absolutely NOTHING about koi ponds.

This blog is dedicated to providing helpful hints and information for koi pond hobbyists - as well as those of you who just inherited a koi pond and are thinking NOW WHAT?
Learn More About Me

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