top of page

Essential Pond Maintenance for Spring

Spring has sprung here at Keruto Koi, and we are excited to showcase all of our fantastic fish now that Winter is finally (almost!) over. Of course, as Winter ends, maintenance and preparation are needed to get our ponds back looking beautiful and ready to enjoy throughout the year. In this blog, we will talk about the maintenance we do here at the start of spring and what you should be doing for your ponds too.

Hopefully, you have done some preparation for the colder winter months. If you are unsure as to what you should have been doing, have a look through our ‘Pond Maintenance’ blog posts here: where we have looked at some of the different aspects of pond maintenance, especially in the run-up to winter. The process of preparing your pond and your fish for winter is often referred to as ‘winterising’ and it is a well-known fact within the koi-keeping hobby that the more preparation you do for winterising, the less maintenance is required in spring for the ‘de-winterising’ and the less the chance of fish getting ill or even passing away over winter.

*Always ensure that when your hands are in your ponds, you are wearing long gloves, ideally elbow-length, so that no toxins from your hands can enter the water.

Plant and Vegetation Maintenance

Hopefully, you should have started to see your lovely pond plants coming back to life after winter by now. Spring is a truly beautiful time of the year for plant life with all of the beautiful colours appearing and becoming more and more vibrant each day.

The beginning of spring is the best time of year to inspect your plants and plant pots. If you have potted plants, you should have a good look at each of the pots and if they are looking a bit full, you can either separate the plants into multiple pots, if the specific plant allows that, or you can repot the whole plant into a bigger pot. This is also the best time of year to introduce new plants to your pond as they will have plenty of time to settle and grow to their fullest for summertime and the risk of frost damaging them should have passed by now.

Finally, you could consider feeding and fertilising your plants during early to mid-springtime. Over-fertilising can lead to plants being affected by stunted growth and becoming weak to pests and diseases. Therefore, it is best to fertilise your plants once per year and springtime is the best time of year to do this as it encourages strong, leafy growth as well as flowering and producing fruit and seeds at the right times during summer and autumn.

Pond Cleaning and Repairs

During autumn and winter, hopefully, you have been keeping the surface of your water clean by removing any dead leaves and organic matter that has fallen into the pond. If there is anything remaining on the surface of the water, be sure to use this time to quickly scoop all of this out before it breaks down in the warmer weather and affects your water quality. We like to use a square-headed net like this one:

This shaped net is especially good as it allows debris to be easily collected into the corner and quickly removed with little effort.

As mentioned in our blog post ‘Essential Pond Maintenance for Autumn’ which can be found here:, one of the most important jobs in the run-up to winter is giving your pond a good clean. Over time, the base and the inside walls of any pond will have a build-up of decomposed matter often referred to as pond sludge. This pond sludge is not great for the health of your pond and your fish so should be cleaned out regularly. The best time of year to do this is in autumn but it could also be done as part of your de-wintering routine in spring, or even done in both spring and autumn. Cleaning out the pond sludge is strictly only necessary once per year as it is a time and labour-intensive job but if you have the time to do it twice a year, this can be really beneficial to the health of your pond and your koi, and it will keep your pond looking its best.

When it comes to cleaning your pond, you should only need to completely empty the pond if the sludge is more than 3-4 inches thick or you have a bottom drain that is either blocked or broken. Otherwise, you can just remove the same amount you normally would for a water change. For smaller ponds, you can then use a net, such as the squared-headed one mentioned above, to scoop out as much sludge as possible. A net is not recommended but it is a good alternative to koi keepers on a budget. You will need to take care to not disturb the sludge into the water too much as this can disturb and damage your koi fish. A pond vacuum will remove a lot more than a net ever could and is much quicker and easier to use. For a large pond, a pond vacuum is an essential piece of kit! We recommend this one from OASE as it is a great size for most small-medium ponds and has great suction power, making the hardest jobs very quick and easy!

While the pond is at a low water level, it is good practice to double-check the liner of the pond and ensure that there are no tears, rips of general areas of particular wear and tear. This is especially important when the liner is up against brickwork or other rough materials as the liner can quickly become damaged. If you do notice any damage or points of wear on small areas, these can be easily fixed using a small patch of excess liner.

Pond Equipment

Firstly, if you normally have a UV clarifier as part of your pond setup, you should have removed this as part of your winter preparations. UV clarifiers are not necessary during the colder winter months, so it is recommended to remove them over winter to prolong the life of the UV bulb and prevent frost damage to the equipment. Once spring begins and the temperatures rise, your UV unit can be refitted to improve the clarity of your water and prevent large amounts of algae. This is also a good time to check the clarifier over for any damage or general wear and replace the UV bulb. It is strongly recommended to replace your UV bulbs every 8-12 months to ensure the UV clarifier performs at its best.

If you don’t already have a UV light, it is strongly recommended to add one to your set-up, especially if you have a display pond. The main purpose of a UV clarifier is to reduce and remove algae from your pond water which will help keep the surfaces of your pond clean and eradicate unsightly green water. Spring is the best time of year to add a UV clarifier to your set-up as it will get to work reducing algae straight away so that by the end of spring and beginning of summer, your pond will be in the best condition for viewing! We strongly recommend the EVO UV Clarifiers from Evolution Aqua, available in 6 different sizes depending on your requirements and the size of your pond:

Finally, you should be using this time of year to have a good look at all your equipment and ensure it is in tip-top shape for the year ahead. Ideally, you should inspect all your equipment, including pipework and fittings to ensure there is no damage or wear to address but the most important bits of equipment to check are your filter and pump as these are the most likely to require maintenance and are vital pieces of kit for the survival of your koi. If you have not noticed any performance issues, then a quick visual inspection should be enough to uncover any issues. It is also a good idea to do a big clean of your filter to ensure that a build-up of grime is not affecting the performance of your filter.

Feeding Your Koi

Over the colder, winter months, you should have noticed that the behaviour of your koi had changed. Typically, koi carp will go into a type of hibernation called torpor in the winter. In this type of hibernation, the koi will appear to be sleeping most of the time, but they are actually just slowing all their behaviours down. In this state, they will be able to save energy by lowering their body temperatures and reducing all of their primary body functions, such as metabolism and breathing. This all allows the koi to survive the potentially freezing weather of the winter months.

During this time of torpor, the koi will not want or need to eat food. Therefore, during autumn and into the start of winter, you should have been feeding your fish a special wheat germ diet in order to help them build up their fat stores in preparation for the period of torpor. A good wheat germ food is this one from Coppens, available in 3mm and 6mm pellet sizes:

As the temperature decreased below 12°, the feeding should have been decreased and then stopped when the temperature fell below 10°.

Well, the exact reverse should happen as the temperatures rise during spring! As the water warms up, your koi will become more and more active until they are fully out of torpor. In order to support your fish the best, firstly, once the temperatures are consistently above 10°, gradually start to reintroduce small amounts of the same, easy to digest, wheat germ food from autumn. A good rule to follow for general feeding is to feed as much food as the fish will eat in 3 minutes. You should continue to do this throughout spring and once the temperature is consistently above 15°, you can transition back to your koi’s normal food in time for summer.

Hopefully, you are now ready to de-winterise your koi pond and ensure your fantastic fish are as prepared as possible for the new year. The more preparations you take before and after winter, the better the chance of your koi being happy and healthy for summer. And, of course, if your koi are happy and healthy, you will have a beautiful pond to enjoy all summer long!

501 views2 comments

Recent Posts

See All


Pond Liner
Jun 26

Good pond maintenance blog. If you'd like to avoid leaks and maintenance, choose a quality product. Pond Pro 2000 is the only liquid butyl rubber in the world. It can be easily applied to all types of surfaces like fountains, waterfalls, pools, ponds, and many more. It's a primer-free, one-coat solution. It's available in black and white colors and quarts and gallons. It's UV-resistant, puncture-resistant, and non-toxic, so it's 100% safe for fish, plants, and other aquatic life within the pond.


Robert Sorrenson
Aug 25, 2023

I want to recommend you email marketing that remains essential for all businesses. Its targeted approach delivers tailored content, nurtures customer relationships, and drives conversions. With measurable results and cost-effectiveness, it's a versatile tool for sustained growth and engagement.

bottom of page