Learn our recommended tips and tools for Koi pond owners to follow for spring pond opening.

Opening your pond in spring is the most dangerous time for your Koi. If you do it wrong, your Koi can get sick. If you do it right, they will thank you; and you will enjoy the rest of the Koi season with peace of mind. We have over 50+ years caring for high quality Japanese koi and have raised many Koi Grand Champions.

Please ask us any other questions you have in the comments section or visit one of our Kodama Koi & pond supply retail stores for more information. If you are looking to shop online you can also Buy Live Koi Fish Online from our farm in Hawaii to add that extra sparkle to your pond this year.

Table Of Contents – Spring Pond Opening Tips:

Learn more about how to choose koi for pond in this educational article. 

WATCH – Spring Pond Prep Tips for Opening a Successful Season

5 Tips for Opening Pond in Spring


1. Monitor Water Temperature

This is very important. Please don’t do anything until the water temperature is stable from 50–55 F. I am still surprised to know how many people do not have a floating pond thermometer in their ponds. Koi are cold-blooded animals. In other words, they cannot control their body temperature; rather the environment or water temperature, in this case, determines Koi’s body temperature and controls their behavior.

Knowing water temperature is essential throughout the season because it guides us on what to do, especially at the beginning of the season. If you do not have a thermometer, please buy one. You can buy an inexpensive one or something like a Seneye Pond Pack that shows the temperature on your smartphone.

It is also a good idea to check basic water parameters at the same time. Please check at least pH, Ammonia, Nitrite and Alkalinity. Make sure your pond maintains the healthy environment for your Koi.

water lilies


2. Treat Your Koi Pond

Once the water temperature is stable around 50–55F, your Koi will be active and start looking for food. BUT wait. You cannot feed them yet.

After long fasting season, Koi are weak. Their immune systems are very low. We need to take care of any potential parasitic and bacterial issues first. If parasites are in your pond system, they will attach to your Koi before they are active and ready. I usually recommend Terminate (or Proform C) and Koi Prazi because they stop most parasite problems. I recommend these treatments at a season’s beginning and end—only twice a year. Koizyme is also an excellent product to prevent bacteria issues. It is not a chemical (that is why I like it). It is beneficial bacteria that naturally eliminates bad bacteria like Aeromonous or Pseudomonous and minimizes the risk of ulcer problems in your pond.

Using koi clay will also help reduce diseases. Before you use any medicines, please make sure you know the total gallons of your pond. You don’t want to overdose or underdose the medicines for your Koi.

Bio Clean filter


3. Activate Your Filter / Clean Filter

Are you using mechanical filter (beads filter) or biological filters? Either way, if you stop your filters during the winter, you need to restart the nitrogen cycle. Please clean inside the filter. If there is any water or wastes left, please drain them all out and clean the filter. Once you clean it, please run your filter.

Here is an important step: Add beneficial bacteria to your Koi filter or pond. After winter, you have little bacteria to help establish the nitrogen cycle. So we need to seed the bacteria. While there are many products of beneficial bacteria online, my personal recommendation is Niigata Water Bio Balls. It has been a popular Koi pond product in Japan for the last 30 years. Each small tablet contains around 20 billion bacteria and their food to multiply themselves. Since these bacteria can live in temperatures as low as 41 F, this is a perfect product for spring—when water temperature is still unstable, but we want to establish the cycle as soon as possible.

If you are fortunate to live where water temperatures are over 50 F even in winter, you probably do not stop your filter and can feed your Koi lightly.

In this case, you do not have to clean your filter. But adding Niigata Water Bio is recommended to boost the nitrogen cycle. “I’ve always found that preparing your koi pond filter system properly in the Spring is one of the most important factors for a successful season.” – Koi Hobbyist – Chase Ohlson Freelance Web Developer in Los Angeles

Close-up of koi group

4. Be Patient in Feeding in Spring

Feed the right food and right amount at the right pace. We all enjoy feeding our Koi. That is the best part of the hobby. However, please do not rush to feed them yet.

Although the water temperature may be good and your filter activated, your Koi are not as ready as you are. They are just coming out of a long fasting season. They are hungry, but their bodies’ systems are not ready to eat normal food. When we are weak from sickness, we eat something soft like chicken noodle soup, don’t we? Your Koi need to start with something soft, digestible, and nutritious.

What do we feed the Koi? Some people soak pellets with water and feed their koi that. That is good, but it could cloud your pond water. Many people love Manda Fu Koi Food. No other Koi food can beat 98.2% digestion rate of Manda Fu. Because of its digestibility, this food can also be fed in water temperatures as low as 45 F. Being digestible is only one feature of Manda Fu. A nutritious enzyme called Manda Nishiki is injected in the food so that Koi can eat digestible and nutritious food in spring.

How often do we feed them? We cannot rush. For water temperatures between 50–55 F, feed Manda Fu once every few days as it gets warmer. Then for 55 F and up, feed regular food like Kodama Koi Food All Season; and start with once a day. Please read our detailed koi feeding guide for more details.

5. Koi Pond Cleaning for Spring

Some people have rocks at the bottom of their ponds. If you are one of them, you may need to move your Koi temporarily and clean the pond even before you start treating and feeding your Koi. Otherwise, debris between rocks will create issues and affect water quality and your Koi’s health.

I do not recommend rocks in Koi ponds because you have to move and stress your Koi almost every year; and they harbor a source of potential Koi health issues. If you must leave the rocks in this year, please do so. But I recommend you consider removing all the rocks from your Koi pond at this time.

Ensure that you take your time in Spring cleaning and be vigilante on clearing string algae within your pond algae control methods. Keep all these tips in mind to help your Koi have a safe spring. And enjoy this wonderful Koi season.

Our Recommended Koi Care Products For Spring Pond Opening

We hope these items help you have a fun and stress free pond opening in your koi pond. Remember to keep that water healthy and check your parameters often! Thanks for reading.

manda-fu-koi-food Manda Fu Koi Food To add extra enjoyment to your time feeding koi, keep Manda Fu in your hand for easy petting. In the summertime, your koi will love this as a treat.

It is also suitable for autumn, winter and spring. You can feed when the water temperature drops as low as 45°F to 50°F. Buy Manda Fu Koi Food

niigata-water-bio-filtration-bacteria Niigata Water Bio Balls One tablet contains about 20 billion bacteria and the bacterias’ food.

These bacteria help filtration and dissolve upon contact with water while multiplying the bacteria to help remove Koi waste, leftover food, and other debris.

They can live in water temperatures as low as 41F degrees (5c degrees). It is best to dissolve the tablet in a bucket of water before pouring it into the pond. Buy Niigata Water Bio – Filtration Bacteria

Kodama Koi Food – All Season (Wheat Germ) Kodama Koi Food – All Season/Wheat Germ is best for maximum koi growth and health, and its digestibility will allow you to feed your koi all year round.

Wheat germ oil is widely known and used as human health food. The remaining defatted wheat germ is used as an ingredient for koi food. Kodama Koi Food, uses the FRESH wheat germ before the oil is extracted.

This keeps your koi healthy and improves its beautiful skin. Bio Stone with silicon aluminum is added to not only keep koi healthy but also helps maintain good water quality by absorbing ammonia. Buy Kodama Koi Food – All Season Wheat Germ

Seneye USB Pond Pack Seneye USB Pond Monitoring Pack The Seneye USB Pond Pack monitors your pond’s vital stats and alerts you if its levels go off balance so you can take action.

This guards your koi from ammonia poisoning and extreme swings in pH levels and water temperature. You’ll be able to remotely view your pond’s parameters on a PC or smartphone from anywhere in the world (or your living room couch) with an Internet connection. Buy Seneye USB Pond Monitoring Pack

TERMINATE Specially formulated treatment for salt resistant parasites and fungal disease!

Strains of salt-resistant koi pond parasites, like costia and trichodina are becoming more common every day.

TERMINATE is specially formulated to treat these tough salt resistant parasites. TERMINATE is one of the most effective Malachite Green (chloride) & Formalin products on the market. Safe for treating costia, chilodonella, ich, oodinium and fungal infections Buy Terminate

Koi Prazi Koi Prazi Praziquantel is used for the treatment of worms.

Flukes (gill and body) are a parasitic worms. Many times when the koi are flashing or you have new koi in the quarantine, they will have flukes.

Koi Prazi is 100% Praziquantel with zero additives; thus giving the best possible rate of absorption into the pond. No additives or fillers are used. When you suspect that your koi may have flukes, then Koi Prazi or Aqua Prazi is the choice. Buy Koi Prazi 

Koizyme KoiZyme KoiZyme is a biological formula of naturally occurring bacteria, enzymes, and micro nutrients. When KoiZyme is introduced into pond water that is infected with Aeromonas, Pseudomonas or any gram negative or gram positive bacteria, the bacteria and enzymes in KoiZyme competes with these pathogens for the nutrients in the pond water.

These nutrients are primarily a nitrogen based nutrient from fish waste. KoiZyme will consume these nutrients and thus starve Aeromonas and Psuedomonas. The bacteria counts (CFU’s) of these pathogens will then be reduced to such a low level that they will not have an effect on your fish. Buy KoiZyme

Further Reading About Koi

Read this other article for more specific tips on opening all types of ponds in the spring from Nualgi Ponds and pond water quality expert Christian Shostle. He goes on to mention the importance of koi clay in your pond for happy healthy fish. Which is another great topic for you to read later!