Why Does My Koi Fish Stay at The Bottom of The Pond? {Are They Sick?}

Are your koi fish sticking to the bottom of the pond? It strikes me as odd and leaves me confused. Why does my koi fish stay at the bottom of the pond?

Are they hiding from you? Are they scared? Is there anything you need to do for them?

I will cover this topic and elaborate on koi fish behavior in this article and more below.

Why Does My Koi Fish Stay at The Bottom of The Pond?

Koi prefer the bottom of your pond simply because that’s where the best quality of oxygen is for them and it’s generally the safest part of a pond.

You can improve the quality of the oxygen in your pond by adding a pond air pump that you can purchase from amazon.

If your pond has frozen over, your koi will go to the bottom of the water column, which is significantly warmer.

Why Does My Koi Fish Stay at The Bottom of The Pond

Do Koi Rest on The Bottom of The Pond?

Yes. Your koi don’t just prefer lower depths just for the better air quality, but the bottom of your pond also provides a safe place for your koi to:

  • hide
  • sleep
  • hibernate

Another reason that fish stay down at the bottom is when they’re sick. They just don’t want to waste the energy swimming up to the top, so they will stick where they are, down deep.

Why Are My Koi Fish Hiding At The Pond Bottom?

Allow me to explain 3 major reasons why the bottom of the pond is a frequently habited place for koi fish.

  1. It’s A Safe Place to Sleep
  2. There’s Warmer Water
  3. Fish Suffering from An Illness

1. It’s Safe

The bottom of your pond is safer for your fish to sleep than the top. They can rest easy, knowing predators like cats and birds can’t get to them.

You may not ever see your koi asleep, but they do rest for short periods. In fact, they sleep with their eyes wide open, just floating away in their chosen spot.

2. It’s Warm

Opposite to hot air rising on land, the water is actually warmer down below. In the winter, when the pond is frozen, your koi go down to the bottom to hibernate. They remain there, staying dormant until the spring thaw.

3. Illness Has Struck

A koi may also be sticking down at the bottom because it’s suffering from some sort of sickness. If you see your koi sticking to one place at the bottom for a longer time than usual, that’s probably the case. Another thing to look out for is head-banging against the edge, which may be due to parasites.

YouTube video

What Should I Put on The Bottom of My Koi Pond?

Placing things on the bottom of your pond like gravel or plants makes a clean, natural bottom for your pond and it helps to boost the quality of the water by attracting beneficial pond bacteria.

Here are some of the things you can put at the bottom of your pond to increase water quality and your koi’s quality of life.

  1. Aquatic plants for shade, hiding spots, and food for microorganisms that your fish will eat.
  2. Sand or Gravel for cleaner water and promotion of pond bacteria to break down filth.
  3. Pebbles for a pond-bottom that looks natural and also promotes healthy bacteria.
  4. A drain on the bottom of your pond for easier cleaning and refreshing the water.

The bacteria will settle on the plants or rocks and will break down decaying organic matter that could otherwise harm your fish. I can recommend Marineland activated carbon which you can purchase here 

Is It Normal for New Koi Sitting at Bottom of Pond?

Yes. New koi fish that are being introduced to your pond may be undergoing some severe stress at first. It could take up to 72 hours for new koi fish to adjust to the pond life around it.

Once this koi fish has adjusted, alertness and speed will arise and they will make more effort to interact with other koi fish and yourself.

If your new koi fish continues to remain at the bottom of the pond and not move around much, that could be an issue with water quality or parasites within it. Sometimes a koi fish is undergoing hypothermia if the temperature is too cold.

Do Koi Rest on the Bottom of Pond?

Yes. Sometimes it’s okay for koi fish to rest at the bottom of the pond. They are resting for a few minutes at a time when they are found lying motionless.A healthy and happy koi fish will do this from time to time.

  1. If your koi fish is resting at the bottom of the pond for the majority of the day, their metabolism has probably slowed down.
  2. If it’s during the winter season, this is quite normal. They are storing their energy and slowing down their swimming behavior.
  3. If the pond is completely frozen, it is natural for koi fish to swim towards the bottom of the water column and stay there until temperatures warm up.

The bottom of the pond is warmer than the top when it is frozen over.

How Do I Clean the Bottom of My Koi Pond?

Cleaning the bottom of your pond can be much simpler than draining all of the water and physically cleaning your pond, but that doesn’t mean you won’t have to now and again.

That being said, there are things you can do to keep the bottom of your pond cleaner, meaning you won’t have to scrub the liner as often.

Here are some things you can put in your pond to help the liner stay cleaner for longer.

1. Adding Sand, Gravel, or Pebbles

Adding natural materials like this not only helps the pond look more authentic, but it helps the whole health of the pond as well and it will hold your pond liner in place.

Gravel, sand, and pebbles all play host to colonies of beneficial pond bacteria that help to break down decomposing material like rotting fish food and traps the heavier gunk down at the bottom, where it is also broken down.

2. Having A Bottom Drain

Building your pond with a water drain is one of the best and easiest ways to clean your pond. You can also get one installed in your current liner, but it is easier to have it pre-built.

When you drain the water from the bottom, you can quickly remove debris from your pond and change the water in your pond with less than half the hassle. There are other benefits, but we’ll get to that in a moment.

3. Drain and Scrub:

There’s really no better way to ensure that the bottom of your pond is squeaky clean than actually doing it yourself. It may be hard work, but it’s worth it to have a clean pond and fresh water for your koi and other aquatic life.

To do this: net your fish, and simply drain your pond. When it’s drained, you’ll be able to remove everything and scrub the liner until it’s clean. Remember to rinse twice when you’re using any cleaners.

Another reminder: doing this quickly and carelessly may stress your fish, so make sure to remove and replace them in the water delicately and remember to restore the same water temperate to avoid shock.

YouTube video

Do I Need A Bottom Drain in My Koi Pond?

No. Technically you don’t need a bottom drain, but it is better in the long run for your pond’s cleanliness and overall health. In fact, larger ponds that are heavily stocked will require multiple drains for easier cleaning and better water quality.

Here are some of the benefits of having a bottom drain in your koi pond:

  • Helps the filter do a better job by draining the bigger gunk, making way for the smaller more harmful materials.
  • When debris like plants and leaves get caught within the rocks, you can easily solve the problem by cleaning the pond.
  • Helps to maintain a better quality of water through simple drainage.
  • Makes it much easier to do regular or complete water changes without stressing fish.


There might be several reasons why your koi is hiding and not coming to the surface. But with a little trial and error, you should be able to find out what’s wrong and get your koi back to the top of the pond.

Thanks for visiting HelpUsFish.com for this article. Check out our home page and search bar with hundreds of aquatic or marine life articles to choose from. Bye for now!


Hello, I'm Jason. I'm the guy behind HelpUsFish.com. I volunteer at my local fish shop and I created this site to offer tips and advice on the fish I care for.