Why Are My Koi Fish Hiding Or At The Pond Bottom?

Why Are My Koi Fish Hiding Or At The Pond Bottom?

Koi fish hiding beneath lily pads

Have you ever seen your koi fish hiding out at the bottom of your pond instead of near the surface where they usually swim? Are you frustrated by their sudden shyness and wondering what’s causing this behavior?

It can be frustrating when your koi friends seem more interested in hiding at the bottom of the pond than coming up to the surface to say hello. After all, one of the joys of having a backyard pond is watching your graceful koi swim and interact with each other.

In this blog post, we’ll explore some of the most common reasons for koi fish always hiding and explore some solutions to get them back to their usual spot near the top of the pond.

By the end of this post, you’ll understand how to create a healthier and more inviting environment for your koi fish, ensuring they stay happy and visible.

Key Points

  • Koi fish often hide due to stress from recent changes in their environment, such as the addition of new fish, seasonal transitions, or alterations in water quality.
  • Predator presence, such as herons and raccoons, can make koi fish feel threatened and drive them to hide more frequently.
  • Creating a healthier environment through proper pond design, aeration, and the use of fish shelters can encourage koi to come to the surface and be more active.

Why Are My Koi Fish Hiding?

Koi fish have several reasons for hiding. One of the main reasons is that it’s a self-defense mechanism. When people are scared, they either fight or run and hide. Fish aren’t known for their fighting skills, so they hide instead. By hiding, your koi fish are protecting themselves from some form of danger.

Let’s take a closer look at 11 reasons why koi fish hide.

1. Have You Recently Added New Fish?

After adding new koi fish to your ecosystem pond, they’ll be a bit skittish. Koi are social creatures, and they may be trying to adjust to new koi fish in the group.

It’s like moving into a new home.

You want to get all settled in before you go exploring and meeting neighbors, but unlike your neighbors, any fish you have may hide! If this is the case, give them some time to acclimate, and they should return to the surface soon enough.

It may be a while before they all come back out, but you can try to use food and coax them out.

Try giving them a week or so to acclimate before you start worrying. If your koi fish stay on the bottom after that time, it’s possible that they are feeling threatened by the new fish, and you may need to rehome one of them.

If it’s not because of new fish, it could have something to do with the water.

2. Have There Been Any Changes In Water Quality?

Diagram of where to place aerators in a pond during summer and winter

Change is stressful, even for koi fish. Water quality, pH levels, or oxygen levels changing can be the cause of your koi fish always hiding.

You’re going to need to test the water, which is as easy as making brownies–just follow the directions! There are test kits you can buy that’ll quickly give you a pH reading by adding a solution to a sample of the pond water. Test it in the morning and evening to get an average pH level.

Low Oxygen Levels

You’ll want to use an aerator to oxygenate the water.

This is especially true for the summer when water holds less dissolved oxygen. Without the right levels of dissolved oxygen, your fish can start having health problems. You can easily add artificial aeration if needed.

Also, be sure to check your skimmer regularly because it may need cleaning or a replacement of the filter mats.

3. Have There Been Any Recent Visits From Predators?

Heron in a pond

Herons, raccoons, and other predators like to hunt in ponds. This can cause your koi fish to hide more often out of fear of becoming a snack for a predator.

One of the best ways to protect your fish is by installing fish tunnels or caves

You could also install a motion-activated sprinkler and put it near the pond. It’ll spray any predator bold enough to try fishing in your pond, including cats. Of course, this isn’t always a permanent fix because, after a while, predators may realize it won’t harm them.

4. They May Be Feeling Sick

Stressed or sick fish will also hide.

These sicknesses have medications and are treatable. You can also use salt treatments.

Just make sure to contact a fish professional before adding anything to your pond. The medication can be tricky, and treating the water with salt can harm the plants.

5. Poor Quality Fish Food

Another reason why your koi fish hide is that they’re not getting enough nutrients from their food.

This is usually due to feeding them poor-quality food that doesn’t contain all of the necessary vitamins and minerals they need.

To remedy this, switch to a high-quality pellet food designed specifically for koi and make sure that you’re feeding them 2-3 times per day.

6. Stagnant Pond Water

Stagnant pond water can also cause koi stress, which then leads to hiding.

Stagnant water doesn’t have enough oxygen in it for fish to breathe, so it’s essential to make sure that your pond is properly aerated.

You can do this by installing an air pump and diffuser or by installing a waterfall or fountain. These devices will help circulate the water and add much-needed oxygen.

7. Seasonal Changes

As seasons change, especially transitioning from fall to winter, koi fish might hide more frequently.

Colder temperatures can slow down their metabolism, making them less active and more inclined to stay at the bottom of the pond, where the water is warmer.

8. Lighting Conditions

Koi fish can be sensitive to lighting conditions.

If the pond is exposed to too much direct sunlight or artificial lighting, it might cause the fish to hide. Providing shaded areas or adjusting lighting can help create a more comfortable environment for them.

9. Pond Overcrowding

An overcrowded pond can lead to stress and hiding behavior in koi fish, as it does with most fish.

When there are too many fish in a small space, they compete for resources like food and oxygen, leading to increased stress levels. Ensuring the pond is not overcrowded and providing ample space for each fish can alleviate this issue.

10. Lack Of Cover

If a pond lacks natural or artificial cover, koi fish and other fish might feel exposed and vulnerable.

Adding plants, rocks, or other structures that can serve as hiding places can help them feel secure, reducing their need to stay hidden all the time.

11. Poor Pond Design

The design of the pond itself can influence the behavior of koi fish.

Ponds with steep sides or minimal shallow areas can make fish feel unsafe. A well-designed pond with varying depths and plenty of hiding spots can encourage koi to be more visible and active.

How To Get Koi To Come To The Surface

Playing with and feeding koi fish

Now, let’s take a closer look at 6 solutions to the various issues that can cause your koi to hide or lie on the bottom of the pond.

1. Install Fish Shelters

One reason your koi may stay hidden is that they don’t feel safe.

Floating logs or rocks placed around the pond’s perimeter can provide some refuge for your fish, giving them a place to duck into if they feel scared or threatened.

You can also purchase pre-made plastic shelters explicitly designed for koi ponds. Be sure to leave some open space in the middle of the pond so your koi have room to swim and socialize.

Oddly enough, providing your koi fish a “safe space” to hide in will encourage them to come out and socialize more.

2. Test And Maintain Water Quality

Koi are sensitive creatures and will not do well in water that is dirty or of poor quality.

Test your pond’s water regularly using a simple home test kit and take steps to correct any imbalances you find. Water pH imbalances or high levels of ammonia are common reasons why a pond’s water quality may be degraded.

You should also remove any debris from the pond on a regular basis, such as leaves or twigs that have blown in. A clean pond will go a long way towards keeping your koi healthy and happy!

3. Install Predator Deterrents

If you live in an area with herons, raccoons, housecats, or other predators, they may lurk around your pond looking for an easy meal.

Heron decoys can help deter these predators, as can netting placed over the top of the pond (be sure to remove it during winter so it doesn’t trap any falling leaves).

You may also want to consider installing a sonic deterrent device, which emits a high-pitched sound that will help keep predators at bay.

Remember to regularly check on your koi fish to ensure that your deterrent works effectively since some predators may eventually adapt and ignore a deterrent.

4. Treat Koi For Parasites And Infections

If your koi are stressed or sick, they’re likely to stay hidden away from view.

Test a water sample for parasites and pathogens, and follow professional recommendations for treatment if any are found. Often, treating the entire pond is necessary, even if only some of your fish are affected.

Regular cleaning and maintenance will also help prevent parasites and infections from taking hold in the first place.

5. Try A Different Koi Fish Food

One reason your koi might be hiding is that they’re not getting the nutrients they need from their food.

If you think this might be the case, try switching to a different kind of food. There are lots of different types of koi food on the market, so you’ll have to experiment a bit to find what works best for your fish.

6. Improve Pond Aeration And Filtration

Lastly, your koi might be hiding because the water in their pond isn’t as oxygenated or clean as it should be.

Koi, like any fish, needs a certain level of dissolved oxygen in the water in order to thrive.

Low levels of oxygen can occur if the pond lacks enough aeration or the filtration system isn’t working correctly.

If you think this might be the problem, you should clean the pond and ensure the aeration and filtration systems are working correctly.

FAQs About Why Koi Fish Are Hiding

Why do my koi fish hide after I feed them?

Koi fish might hide after feeding if they are overfed. When koi eat too much, they can feel sluggish and retreat to the bottom of the pond to rest. It’s essential to monitor how much food your koi are consuming to prevent overfeeding. In Baltimore, MD, make sure to feed your koi in small amounts several times a day to keep them healthy and active.

Are my koi fish hiding because of new pond additions?

Yes, adding new fish or other elements to the pond can cause koi to hide. They need time to adjust to new fish, plants, or decorations, which might make them feel insecure. In Maryland, consider adding new pond elements gradually and providing plenty of hiding spots to help your koi acclimate to their new environment.

How long do koi fish hide?

Koi fish can hide for several weeks, especially if they are small. They need time to get used to their new surroundings and feel safe. During this period, spend time near the pond to help them become accustomed to your presence. Ensure you provide plenty of hiding spots to make the transition smoother.

Why is my koi isolating itself?

A koi fish might isolate itself if it is stressed, sick, or bullied by other fish. It’s important to monitor the fish for any signs of illness or injury. Providing a calm and safe environment can help reduce stress and encourage your koi to rejoin the group.

Let Premier Ponds & Lighting Help Maintain Your Koi Pond

There are a few reasons why your koi might be hiding and not coming to the surface. But with a little trial and error, you should be able to figure out what’s going on and get your koi to come out and enjoy their pond again.

If you want help maintaining or cleaning your koi pond, fill out our contact form today. We would be happy to answer any questions you may have. 

Koi are such beautiful creatures, so it’s worth taking the time to figure out what’s going on and how to fix it so they can swim around and enjoy their home just like they deserve. Except for in winter, when the pond freezes, you’ll need to care for them in a different way.

What to do with pond fish during winter >>


2 Responses

  1. I noticed one of my koi was getting round and swimming much slower. I think it may be pregnant.
    My indoor pond is flat bottom. I thought there will be no place for the eggs and frys. So I added a few stones to the corner of the pond and my koi are completely avoiding that corner, even after 2 days.
    How long does it take for them to get use to the stones?
    Should I remove the stones?

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