When Do Koi Fish Come Out Of Hibernation

Koi fish are interesting creatures that hibernate like some land animals during the winter. Koi fish owners need to know as much as possible about Koi fish hibernation as it can change their care requirements. So, let’s look at what you must know about Koi fish hibernation.

Koi fish will begin their hibernation at the beginning of winter when the temperatures start to fall. They will hibernate throughout winter and only start coming out of hibernation and returning to their normal behavior in the early spring when the temperature reaches 50°F.

What happens to a Koi fish while they are hibernating? How do you care for Koi fish that are hibernating? How do you help your Koi fish prepare for hibernation? Let’s find out!

Pro Tip: If you’re tired of wasting money and making costly mistakes on the koi-keeping hobby or are thinking about buying koi fish but don’t know where to start, I strongly suggest you check out this ebook. I recently read this ebook, and it contains SO much useful information, such as: 

  • 3 proven steps to identify koi fish diseases
  • WARNING: 3 things you should NEVER do when it comes to caring for koi
  • When to seek professional help when it comes to looking after your koi

Click Here Now To Check It Out

When Do Koi Fish Hibernate?

Koi pond in winter

Koi fish are beautiful creatures. With more and more people becoming Koi fish owners, many questions about their behavior and care are popping up. One question is, when do Koi fish hibernate?

The behavior of Koi fish is affected by the weather and water conditions surrounding them. Hibernation is one such behavior that will be triggered by weather. When the temperature starts to fall as winter approaches, the temperature of the Koi’s water will drop too.

This drop in temperature will trigger hibernation in your Koi fish. Your Koi will hibernate through the cold winter months.

When Do Koi Fish Come Out Of Hibernation?

Koi pond in spring

So, Koi fish do hibernate through the winter months, but when can you expect your Koi to emerge from hibernation and go back to their normal activity levels. Koi fish will start coming out of hibernation when the cold winter dissipates.

Generally, in the early spring, you will notice your Koi fish becoming more active. During this time, you need to watch the water temperature, as you should not start feeding your Koi fish as soon as they begin moving again.

When the water temperature reaches 50°F, your Koi fish should return to their normal selves and recover from hibernation. When the temperature gets to 50°F, you can begin treating your Koi fish as normal again.

What Happens When Koi Fish Hibernate?

If you own koi fish, you might wonder what happens to your Koi while hibernating. This is quite an interesting topic, and it is something that all Koi owners need to know and understand to care for their Koi fish properly during this time.

You need to be aware of two main changes in your Koi fish when they are hibernating. These are the change in their metabolism and their immune system. Let’s go through these changes in detail to understand better how to help your Koi fish stay healthy.

The Metabolism Of Koi Fish During Hibernation

When your Koi fish begin hibernation, their metabolisms start to slow down, which is one reason most people stop feeding their Koi in the winter. Koi fish metabolisms are linked to temperature, and as the temperature lowers, the Koi’s digestive system will slow down.

When their digestive systems or metabolisms slow down as they enter their hibernation state, the Koi fish don’t need the energy they get from food as they are no longer active.

If you feed your Koi fish during their hibernation, the food can potentially cause several problems for your Koi fish. If the Koi fish eat during their hibernation stage, the food could cause a blockage in the Koi’s digestive system as they won’t be able to digest the food fast enough. This blockage can kill your Koi fish if left untreated.

This is not the only problem feeding your Koi fish in the winter can cause. If your Koi don’t eat the food you give them due to their slow metabolisms, it can sink to the pond’s floor, break up, and eventually dissolve in the water. This will lower the water quality in the pond and can affect your Koi fish’s health.

Changes In The Immune System Of Koi Fish In Hibernation

The immune systems of Koi fish are linked to their metabolism. When the Koi fish go into hibernation, and their metabolism drops, their immune systems also lower. This is something that Koi owners need to know about and should be concerned about when their Koi are hibernating.

When their immune systems decrease in hibernation, the Koi fish are susceptible to viral and bacterial infections and parasite infestations. For this reason, you must keep your pond’s water clean and free of possible contaminants during the winter.

If an infection of any kind goes unnoticed by you, this can lead to the death of your Koi fish as their immune systems cannot fight it alone while they are hibernating.

How To Care For Hibernating Koi Fish

When the cold winter months finally set in and your Koi fish begin their hibernation, there are some things you can do to care for them during this time. Firstly, there is some controversy about whether or not you should stop feeding your Koi fish during hibernation.

Some people say you should not stop feeding them, but the professionals suggest you should. You should probably go with the professionals on this because, as we mentioned earlier, when Koi fish Hibernate, their digestive systems slow down to a near stop.

So, if you feed your Koi during this time, they will struggle to digest the food properly, which can cause a blockage in their digestive systems, which will require treatment. So, when the temperature drops, you must stop feeding your Koi fish to help keep them healthy during hibernation.

If your pond is susceptible to icing over, then you should invest in a de-icer and some air stones for your pond. In the winter, you need to clean your pond, and the de-icer will help you do this by keeping ice from forming on the water’s surface. This will also give you access to your Koi fish if you need to treat them for any illness. The air stones will help keep oxygen circulating in your pond, ensuring your Koi fish have enough oxygen to survive. These two devices are essential to keep your Koi fish healthy through winter.

How To Prepare Your Koi For Hibernation

Before your beloved Koi fish go into hibernation, you can do a few things to ensure they stay healthy throughout the cold winter months while they hibernate. Helping prepare your Koi fish for hibernation is a great way to ensure you have little to no Koi fish casualties due to the cold.

These preparations can take some time, so you must take a weekend to complete them successfully to help all your Koi fish survive the winter. Let’s go through what you need to do to help prepare your Koi fish for hibernation.

Treat Infections Or Parasites Before Winter

First, we will cover something that quite a few Koi owners forget about: treating your Koi fish for any parasites, infections, or illnesses before the cold winter temperatures come to stay.

You need to treat your Koi fish before the winter as the Koi fish are most vulnerable to these illnesses when hibernating. This is due to the Koi fish’s digestive system slowing down, causing their immune system to lower.

You need to treat your Koi Pond for a wide range of parasites and bacteria that could potentially cause dangerous infections in your Koi fish. You should also examine each fish closely for signs that suggest an illness that may need treatment.

You need closely examine your fish and treat them two months before you expect the temperature in your area to drop below 50°F.

This will help ensure your Koi fish are protected through the winter. You can connect with your local aquarium store to find the best way to treat your Koi Pond to ensure your Koi fish are as healthy as possible.

Clean The Koi Pond Before Winter

You need to clean your Koi Pond thoroughly before the winter months hit. This helps to keep your Koi fish healthy throughout the cold winter season. You must do this thorough pond clean in the autumn before the temperature drops below 40°F.

In this cleaning session, you must dispose of all the waste and leaves in and around your Koi Pond. Doing this will help reduce the toxic gases that can build up under the ice that forms on the pond in winter as there is less plant life in the water to decompose.

You should also do a water change during this thorough clean to ensure the water in the pond is clean and fresh for your Koi fish to live in through winter. This helps to keep your Koi fish healthy.

How To Know If Your Koi Fish Are Hibernating

When the temperatures begin to fall as winter starts arriving in your area, you might be wondering how to tell if your Koi are hibernating already or not. There are a few signs you can look for that indicate your Koi fish have begun hibernating.

These signs are easy to recognize if you know what to look for. If your pond is deep, you may struggle to see these signs but try your best to locate your Koi and see what they are doing. You need to know if your Koi fish are hibernating or not, as this will determine how you care for them. Let’s go through these signs to look for that indicate your Koi are hibernating.

The Position Of Your Koi Fish In The Pond

Koi fish laying on the bottom of a koi pond

When Koi fish hibernate, they will sit at the bottom of your pond with their pectoral fins tucked under their bodies. When your Koi are in this position and don’t move, this is a good indication that they are hibernating.

The Behavior Of Your Koi Fish During Hibernation

When your Koi fish are getting ready to hibernate in the cold weather, you might notice a slight change in their behavior. Your Koi fish may stay closer to the bottom of your pond, where the water is slightly warmer.

They will be searching for a place at the bottom of the pond to hibernate. Your Koi fish will be evenly spaced out at the bottom of the pond, and they will be facing the same direction if you have a smaller pond.

Your Koi will not eat anything and will hardly move during their hibernation, so do not worry if your Koi fish stay still; they are fine. If your pond doesn’t ice over and there is a warmer day in the winter, you might notice your fish sunning themselves closer to the water’s surface.

When Should I Open My Koi Pond In The Spring?

spring koi pond

Koi fish will come out of hibernation in the early spring, but when should you open your Koi pond? Generally, once the snow and ice have melted and the temperatures in your area have been above 40°F for an entire week, it is safe to open your Koi pond again.

Do not open your Koi pond before these conditions are met, as this could trigger your Koi to return to hibernation, which is not what you want. Once you open your pond for the spring, you will need to begin cleaning to rid your pond of any waste that has built up in the winter.

Can Koi Fish Live In Spring Water?

Koi fish are freshwater fish and need a good balance of minerals in their water for them to thrive in your pond. Koi fish can survive quite well in spring water as it has a good balance of minerals and a good pH level.

You should buy different spring water brands and test their pH, gH, and kH levels before placing your Koi fish in them, as spring water quality can change from brand to brand. Alternatively, you can use good quality spring water to help fix the pH levels in your pond or aquarium to make it more suitable for your Koi fish.


Koi fish hibernating is natural, and there is nothing to be concerned about when your Koi fish do it. Preparing your Koi fish for hibernation requires more effort than their regular care. However, ensuring your Koi fish are healthy during this time is worth it.

Your Koi fish will only hibernate for a few months in the winter and should return to normal in the early spring when the temperatures begin to warm up. Good luck with your hibernating Koi fish!










Recent Posts

Verified by MonsterInsights