A Complete Guide To Maintaining A Koi Pond

Whether you’re new to keeping koi or want to sharpen up your maintenance and care, everyone who has one should know how to maintain a koi pond. However, there are many things to do when maintaining a koi pond, and the information can be hard to find. Luckily, I have taken the time to make a complete guide to maintaining a koi pond to help beginners and experts alike.

The maintenance of a koi pond consists of five categories. These categories include daily tasks like topping up water, weekly tasks like removing dead leaves, monthly tasks like cleaning substrate, seasonal tasks like cleaning the pond, and yearly tasks like replacing any necessary equipment.

Though there are many tasks to maintain your koi pond, they can easily be broken up into different categories to help you. However, some of the things you have to do will naturally be easier or more difficult than others. It is best to research how to complete these tasks before attempting them. If you do something incorrectly, you might cause a bit of damage.

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Daily Tasks To Maintain Your Koi Pond

The first category, daily tasks, is primarily straightforward. There are, however, two different aspects that you need to consider and look after. The first part is the koi fish, and the second is the pond itself. Having a nicely maintained pond without any healthy koi is no more the goal than having healthy koi in a poorly maintained pond.

Koi Maintenance

For the most part, the tasks you need to do daily to keep your koi happy are straightforward and logical. These tasks are usually quick and easy to do and will not take much time out of your day. The daily koi maintenance tasks include:

  • Feeding Your Koi – To provide your koi fish with enough nutrients, you will have to feed them daily. Some people feed their koi more often, but they only need the food once a day, and the excess food can cause bacteria to form in the pond.
  • Checking Your Koi – Though you do not need to fully examine your koi every day, many experts will advise you to keep an eye on them. Koi fish has a way of saying what’s wrong if you know what to look for, and it is best to catch any problems early on. Infected koi might have sunken eyes or pale patches, and if there is too little oxygen in the water, the koi might stay close to the air filtration system of the pond. If caught in time, these signs can save your koi and save you time and money.

Pond Maintenance 

Other than looking after your koi, there are also a couple of other tasks that you should do daily. These tasks prevent problems later and keep your koi and pond in good health.

  • Remove Uneaten Food – Removing uneaten food daily is necessary to maintain your koi pond. Uneaten koi food can degrade the water quality of your pond, and sometimes the food releases toxins when it starts breaking apart. The effect of leftover food is more significant in a new pond, but it is best to remove any for health and maintenance.
  • Top Up The Water – Though your pond will likely not lose a significant amount of water during the day, it is always best to keep it topped up. Doing this ensures that your koi are happy and healthy and that there is always enough swimming room.
  • Remove Any Other Debris – There might be some debris gathering on the pond’s water during the day. This debris can include leaves from nearby trees and pieces of plants in the water. It is always best to remove leaves and debris to ensure that the pond stays clean and there are no problems.

Weekly Tasks To Maintain Your Koi Pond

Maintenance that needs to completion on a less than daily basis falls under weekly tasks. These tasks are usually still easy to do, but it is necessary to do them weekly for the best results. Some of these tasks may need doing twice a week.

Koi Maintenance 

Since weekly tasks will probably get done over the weekend, you will have more time to check up on your koi and ensure everything is okay. You need to do just one task weekly to keep your koi happy.

  • Check Your Koi – Though you will already be doing this daily, spending some time with your koi and making sure that everything is alright is necessary. If you see any koi behaving strangely or have any cuts, burns, pale spots, or other damage, you should call the closest vet as soon as possible. Once the vet has helped you understand what is going on, do your best to correct the situation.

Pond Maintenance

Maintaining your pond is a bit more time-consuming for weekly tasks. You have to do a few more things to ensure everything is fine and in good working order. 

  • Clean The Filter System – Keeping the filtration system of the koi pond clean and in proper working order is essential to maintaining your koi pond. If the filtration system isn’t working as it should, your koi could suffer, and you might see their behavior patterns change.
  • Clean The Pump And Skimmer – If you have a koi pond, the importance of a skimmer and pump to keep the water clean is probably not new to you. However, if you do not clean out the skimmer basket weekly and ensure the pump and skimmer are working well, it defeats most of its purpose. 
  • 10% Water Change – To counteract the deterioration of the water in your koi pond, you need to change between 10% and 15% of the pond’s water per week. The best way to do this is to replace water as it drains from the pond. However, if you’re doing this once a week instead of throughout the week, you must ensure the new water is suitable. The simplest way is to fill a large container or blow-up swimming pool, let the water stand overnight, and do the necessary test to ensure the water will not hurt the koi fish. When the water is ready, you can start slowly removing and replacing the water in the pond.
  • Test The Water – If you want to keep your koi and their pond in good shape, you need to test the water at least twice a week. The tests you need to do, include the water temperature, a pH level test, a chlorine test, alkalinity, and an acid test. These tests will help you see what you need to do to improve the conditions of your koi and the water they swim inside.

Monthly Tasks To Maintain Your Koi Pond

There are several tasks you will have to do every month. Completing these tasks will ensure that your pond and its koi are in good shape. These tasks can become more time-consuming, but it is important not to rush them to avoid damage to the pond or the koi. I will also not be splitting these tasks into koi and pond maintenance.

Monthly Maintenance 

  • Test The Water Quality – Though you should be doing this every week, you can do this every month if you struggle to find the time or want to be very sure. All the tests you need to run on the water are above, be sure to do your best to keep the water in the perfect condition for the koi to survive and thrive.
  •  Clean And Move Substrate – The substrate in your pond is what you have put in at the bottom. If you have added gravel, stones, or aqua soil to the bottom of your koi pond, you need to clean and level the substrate at least once a month to ensure it stays clean and provides a suitable habitat for your koi fish.
  •  Clean And Check Equipment – Cleaning your equipment like the pump, skimmer, and filtration system weekly is a brilliant way to maintain your pond. However, doing a deep clean of the equipment is also necessary. 

 At least once every month, you need to give all the equipment in your pond a thorough cleaning and check them for damages and breakages. Staying up to date on all your gear and knowing how when they will need a replacement will significantly help you in the process of maintenance. 

 If some of your equipment, like the filter, is acting up, you should call a professional to see if they might be able to help you fix it before it is too late. On the other hand, if you have been using a specific piece of equipment for a long time and think it might be time to replace it, you can buy the replacement before the original stops working completely.

  •  Check Your Expenses – Doing a monthly check on your expenses and comparing them to the previous month can unexpectedly help you. By looking at what you pay for food, water, and even electricity, you can determine if there are any problems with your pond or your koi fish. For example, if your pond needs more water than usual, there might be a leak that needs fixing.

Seasonal Tasks To Maintain Your Koi Pond

For a koi pond, the change of season brings some extra tasks. You should never overlook these tasks as they are vital to keeping your pond and koi in good shape. Different seasons also have other jobs, so I will break these tasks down by season.


Since koi are more active in summer, maintaining balance and ensuring the water is right is a big part of what you need to do. The tasks below are not the only ones you need to do in summer as the tasks given above also need doing during the summer months.

  • Monitor The Water – Keeping an eye on the oxygen levels, temperature, and other aspects is crucial in summer. Warmer water carries less oxygen, so if you test the water and more is needed, consider adding a second aeration device.
  •  Keep The Temperature Right – Keeping the temperature of a koi pond right during the summer months can be a bit tricky. However, if you can provide your pond and koi with enough shade, that will help you a significant amount.


As with the summer months, you still have to ensure that you keep doing your daily, weekly, and monthly tasks. However, it would be best to do several other things to keep your koi and pond happy.

  • Install a Net – Installing a net over your koi pond can significantly reduce the water’s number of leaves and debris. Doing this will allow you to spend less time cleaning your pond as the trees drop more leaves during this time of year.
  • Turn Off Any Water Features – If you live in an area where the temperatures during winter reach freezing or below, it is best to switch off any water fixtures that might be running. If you leave your water fixtures on, you might waste water as ice might form that pushes the water out of the pond.


At the end of fall and the start of winter, there are two crucial things that you must do. These tasks are essential to ensuring the survival of your koi and are a critical part of maintaining your koi pond.

  • Winterize Your Pump And Filter – It is essential to winterize your pump and filters for the winter months. If you do not do this, your pump and filters might be damaged and need replacing or repairs.
  • Ensure Your Pond Does Not Freeze Over – If you keep your koi in the pond during winter, something many people do, you will need to ensure that your pond does not freeze over. There are two common ways, and some less common, to do this, like adding a de-icer to your pond or adding an extra aeration device.


After winter and at the start of spring, you will be undoing what you have done to winterize your koi pond. There is also another thing that you should do to ensure that your koi are healthy.

  • De-winterize And Monitor – The first thing you need to do is de-winterize your pond. Once you have done that, you will need to keep a close eye on your koi to ensure none of them are sick or infected. If any of your koi are infected, you should call a vet immediately. 
  • 20% Water Change – Once winter has passed, you will need to do a 20% water change to ensure that the water in your pond is suitable for your koi. You can do this over time to gradually adjust the water. The steps for this process are the same as the weekly version.

Yearly Tasks To Maintain Your Koi Pond

If you have been following all the steps and have been monitoring and maintaining your koi pond, the chances are that you will not need to do the following. However, this task is still essential and needs doing at least once a year.

  • Check And Replace Gear – Depending on when you are doing this; you might have just gone through winter. Winter can be very taxing on the equipment used in a koi pond, so it is essential to check, clean, and replace any equipment used in your koi pond.


Having a koi pond housing healthy koi fish can be a great feeling and liven up your home. However, without proper maintenance, things might begin to fall apart. You must ensure your pond is always clean and in working order. Doing this will save you money and expand the life expectancy of your koi fish.

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