April 27

Sarah Robertson

What Do Koi Fish Eat? The Ultimate Koi Food Guide

Seeing your Koi come to the surface to feed is one of the most enjoyable aspects of being a Koi owner. However, providing your koi fish with the best koi food is also one of the most essential and difficult tasks in caring for them.

What you feed your Koi dramatically affects how big they get, the vibrant color of their scales, and how healthy they are.

That's why it's critical to have a firm grasp on what you should feed your Koi to keep them happy, healthy, and looking their finest. Koi fish food is expensive, but it's critical to get the most out of your money by providing your fish with the appropriate diet.

Koi fish will eat anything that comes their way, whether it's specialty food, human food, or whatever else happens to end up in their pond. In this post, we'll look at what koi fish eat in the wild. We'll go over what you should and shouldn't feed them, as well as answer any other questions that may be on your mind.

What Do Koi Fish Eat? 

Koi fish are omnivores with a powerful digestive system. They have been known to eat algae, plants, animal matter, flies, and bugs in the wild. The best Koi food is one that contains all the necessary minerals and vitamins for keeping koi healthy.

They also give the fish a constant supply of protein, carbohydrates, and minerals in addition to that. As long as you offer them tiny natural items to swallow, they'll consume just about any natural foods you give them.

Koi, like other fish in captivity, can be fed a wide range of foods. They will eat fruits and vegetables, as well as carbohydrate-rich options like bread, rice, and cereal.

They will even consume small amounts of protein sources like shrimp or chicken chunks. Koi, like people, require a balanced diet that consists of carbohydrates and proteins as well as a little fat.

If you're feeding your Koi several times a day, alternate which meals are high in carbohydrates and which are high sources of protein. Alternatively, if you get a pre-mixed Koi food, it will contain enough of both for your fish.

Most koi are fed wheat germ pellets, which include all of the necessary nutrients, vitamins, and minerals. Carbs can be given in the form of squash, peas, fruits, and watermelon to koi along with the pellets.

How Does Food Affect Koi Fish Color?

Vitamins in the diet have an impact on a Koi's scales, which affects its color.

In general, red is the color most affected by food in Koi because many commercial Koi foods have varying proportions of carotenoids.

Carotenoids are the pigments that give your Koi fish their brilliant orange, yellow, and red hues. Giving your fish enough carotenoids can even begin to make white markings turn pink.

However, don't expect new food to immediately alter the color of your fish. The color of your koi can be altered by feeding them over days and weeks.

How to Choose Koi Food to Maximize Health, Growth, and Color?

Choosing the ideal diet for your Koi is an important component of ensuring their optimum health, development, and color.

Although there are many different types of business Koi food on the market, a lot of the low-cost foods fail to contain the proper combination of carbohydrates, proteins, nutrients, and vitamins for your fish to thrive.

There are two common additives to look for in Koi food:

Spirulina is a algae that contains a lot of carotenoid vitamins, which may enhance the red color of your Koi fish. Spirulina is high in protein content and beneficial to the immune system of Koi, which is why many Koi owners like food that includes this ingredient.

However, overfeeding your Koi with Spirulina can actually cause the color of their scales to become excessively red and white spots to turn pink.

Wheat germ oil is another additive, which includes a variety of fats and oils that help your Koi appear bright. Wheat germ oil is high in fat. It's sometimes utilized to promote healthy growth in Koi since it provides them with lots of energy to reach their full potential.

Other types of food that may be beneficial to Koi while also enhancing their coloration include krill, which contains carotenoids that enhance the color of your fish and are also a nutritious protein source. To enhance the color of your fish, you may also add particular vitamins to their diets, such as specific kinds of carotenoids or other pigments.

What Can I Feed My Koi Fish

What Can I Feed My Koi Fish?

Koi may be fed just about anything that people can eat. Shrimp, fruit, and vegetables are examples of things you can feed them. Bread and other foods with high stomach loads are harmful to fish. Koi fish can also be fed with fish food pellets, however, make sure they're the proper size before doing so.

The four most frequent feedings for koi fish are:

Spirulina Algae 

Cyanobacteria, often known as blue-green algae, are present in water and create their own sustenance. They are tiny, measuring no more than half a millimetre in length. This algae is free-floating and may be found in lakes with exceptionally high pH and hard water.

The advantages of feeding koi fish with spirulina algae are as follows:

  • The growth rate is expected to be higher.

  • Improving the digestive system

  • Strengthening the immune system

  • Helping prevent swollen abdomens

  • Enhancing the production of specific enzymes that break down fats into energy

  • Because of the algae's carotene pigments, it gives a brighter coloration.

Wheat Germ 

Don't be concerned, it's not a harmful germ. This is the wheat portion that produces shoots and converts to a new plant. Wheat germ has been found to assist koi fish in accelerating their healthy growth. It's also a good source of vitamin E, which promotes blood flow, increases oxygen and nutrient absorption encourages balanced development and aids in disease prevention.

Brine Shrimp

Brine shrimp eat everything in the water they can consume, which isn't much since to their tiny size. The nutrients they consume are carried to the fish they are consumed by, which is known as bio-enrichment. Brine shrimp are a wonderful food for newly hatched koi because they grow quickly.

Fish Food

Flake fish food is preferred by small and baby koi because it's the tiniest form. Pellets are suitable for average-size koi, but bars of fish food is more appropriate for larger ones. The majority of superfoods have a substantial quantity of proteins, a few fats, and all of the necessary vitamins and minerals.

Other favorite foods include earthworms, larvae, tadpoles, shrimp, and clams.

What Can I Feed My Koi Fish

Factors That Affect Koi Feeding

There are numerous elements to consider when selecting what and how much to feed your Koi. These fish grow constantly, and their digestive demands change with the water and seasonal changes.

Koi Size

You must consider the size of your koi when purchasing koi food. Koi food comes in a wide variety of sizes, from tiny pellets to big pond sticks, so you'll need to determine the dimensions of your fish.

Feeding pond sticks to small koi may be problematic because they are unable to chew on them, so it's best not to do it. Feeding large koi tiny pellets will just make eating a time-consuming effort, and they may not get enough to eat as a result.

If you have both big and little koi in your pond water, you'll need to feed them two distinct kinds of food. In this situation, feeding large floating pellets and tiny sinking pellets is often the best option.

The big koi will be distracted by and pursue the huge floating pellets. The small koi will be able to reach the small sinking pellets, while the big koi will not be able to do so. You may feed flakes, bloodworms, and daphnia to the smallest koi.

Recommended Pellet Size For Koi Fish

3/32 inch (2.4mm)

 Koi 4 inches (10cm) or smaller 

3/16 inch (4.8mm)

Koi fish 6 – 10 inches (15-25cm

1/4 inch (6.4mm)

Koi fish 8 – 12 inches (20-31cm

9/32 inch (7.1mm)

Koi fish 10 inches (25cm) or larger

5/16 inch (7.9mm)

Koi fish 12 inches (31cm)or larger


The quantities of carbohydrates and proteins that your Koi require in their diet vary according to the temperature of your pond. This is because Koi are more active in cold water than in warm water owing to the difference in oxygen content.

In the winter, when the water is cold, Koi will be ravenous. You should give them food with a lot of carbohydrates and little protein, such as wheat germ, in this situation.

Wheat germ is easy for Koi to digest while they are swimming about and does not pollute the water as much as protein-rich food.

In the summer, when the water is hot, Koi will slow down and require higher levels of protein to keep their bodies and develop properly. In this season, you'll want to replace your usual meal with one that includes higher quantities of Spirulina or krill protein, and avoid food high in wheat germ.

In the fall and spring, when temperatures are in between or fluctuating, offer your koi a combination of carbohydrates and proteins.

You may feed your Koi a meal that is balanced or feed them two distinct meals in the morning and afternoon.


While the seasons provide a good indication of how much carbohydrate and protein your Koi should consume, you may also measure the temperature of your water to determine how much food to give it.

When the water temperature is lower than 50 degrees Fahrenheit, a high-carbohydrate diet is appropriate.

Protein-rich foods are preferable for Koi when the water is above 70 degrees Fahrenheit. You may feed a combination of carbohydrates and proteins at intermediate temperatures.

Weather Influencing Oxygen Content 

Oxygen content has a significant impact on how your Koi eat and what sort of food they need. In turn, weather can have an important impact on the water's oxygen level.

The ambient air's oxygen content actually falls somewhat when it is raining. Unless your pond is very deep, this will also lower the water's oxygen level.

If you're feeding them too much, they may be less active than usual. You'll probably want to feed them somewhat less frequently and temporarily switch to a more protein-rich diet.

Water temperature can also reduce the amount of oxygen in your pond by heating it up. Because warmer water has less oxygen, your Koi will benefit from a protein-rich diet as previously said.

Water Quality and Pumps Affecting Oxygen Content 

Furthermore, maintaining high water quality is critical in keeping your pond's oxygen level constant. Algae can generate oxygen while growing on the surface, but once they die, they sink to the bottom.

If the algae die and the bacteria that contribute to its demise multiply, your Koi's water quality may deteriorate considerably. The microbes that feed on those dead algal blooming can suck up a huge quantity of oxygen, leaving your fish in anoxic conditions.

If you use pumps, on the other hand, you may artificially boost or reduce the amount of oxygen in your pond's water.

By circulating the water and aerating the pond's water, as well as providing oxygen, turning on the pumps will prevent algae from developing. In this situation, your Koi would most likely be more active and a carbohydrate-rich diet will be preferable.

Floating Vs Sinking Koi Food

Floating Vs Sinking Koi Food

There are a number of different types of koi food on the market, both floating and sinking. Which one you choose is up to you. The best way to make a decision is to try them both and see which your koi prefer. Here is a list of pros and cons for each type:

Floating Food

Floating food is the most common type of Koi feed and according to experts most Koi owners feed floating foods.

The first merit of feeding floating food is that it is enjoyable. It's great to observe the fish in front of you eating their food. The second benefit is that you may check the health of your Koi. Because it floats, koi must come to the surface and you can inspect whether any have been injured.

Depending on the angle, you may notice all the way down to the tummy or other regions where you could not easily check. The third merit is that you may identify who is eating and who isn't. This is yet another approach to assessing the health of your koi. It's simple to tell who isn't hungry.

The disadvantage of floating koi food is that the food may be pulled into the skimmer before your Koi can eat it. It's quite easy to prevent this. If you have access to the skimmer box, you may turn off the pump there. Alternatively, you may close the skimmer. You might also float an O ring so that the food remains within it.

Sinking Food

Sinking food is designed to sink to the bottom of the pond where the Koi can eat it more easily. The main advantage of sinking food is that it's less likely to be pulled into the skimmer and lost before the Koi can eat it.

Another advantage of the sinking food is its rapid development. The food will typically sink to the bottom very quickly, which allows for instantaneous eating.

One of the most important drawbacks of sinking food is that it may accumulate quickly on the pond floor, resulting in foul smells and germs. You'll need to clean your pond more regularly if you decide to switch to a sinking food diet.

While feeding sinking food it is more difficult to observe their eating activities. So if any Koi are not doing well, you may easily overlook that. If water is not clear like mud ponds, you can not tell easily.

In general, both floating and sinking foods have their own benefits and drawbacks. You should try both types and see which your Koi prefer. In addition to the food types mentioned above, you may also try live food like mealworms, crickets, and earthworms.


Why Buy Quality Koi Food for Koi? 

Not only for fish health but also for maintaining excellent water quality, high-quality food is essential.

It is critical to feed high-grade koi food because they include all of the essential vitamins and minerals for keeping koi healthy. They also give the fish a constant supply of protein, carbohydrates, and minerals in addition to that. This causes them to become larger and more colorful. High-end koi food is also more appetizing, so the fish are more enthusiastic while they eat.

How Do I Grow Big Koi and Maximize Koi Growth? 

You can increase the size of your koi by feeding them nutritious food that has a higher feed efficiency and it is fed frequently during their peak activity periods (above 60 °F water temperature), such as in the summer months.

As the temperature rises, your koi's metabolism speeds up. To produce the biggest koi in your pond, you will need to maintain excellent water and feed your fish with food that gives the best feed efficiency.

The feed efficiency is a measurement that indicates how effectively the feed nutrients are converted into body mass. When you feed high-quality koi food, you can expect to have a greater feed intake and growth ratio.

 If you reduce the quality of your food, you'll have to feed more to get the same growth ratio. In the long run, better food will be more cost-effective, allowing you to optimize koi growth potential. This is truly based on the koi's lineage/genetics.

We also recommend using a feeding device that measures time to make sure the koi consume enough food and stay regular. This will let you get the most out of your koi by enabling you to better optimize their growth without polluting the pond.

How Much to Feed Your Koi Fish? 

When feeding fish, we prefer to serve them with a few small handfuls at a time. It's always necessary to adhere to a 5-minute rule when feeding the fish. The five-minute rule stipulates that the fish should be fed only as much food as they can consume in five minutes.

If they consume everything you offer them in five minutes, it's okay to give them some more. After five minutes, if there is still food floating around, it's time to put the food away.

How Often To Feed Koi Fish

How Often To Feed Koi Fish?

It is recommended that you offer your fish food only once a day. This will give adequate nutrition for healthy fish and a healthy pond. Aside from the fact that feeding them continuously can cause algae problems, overfeeding them may result in a surplus of nutrients entering your pond, causing algae to grow.

 With that in mind, if you have clean water and would like to offer your fish twice a day, you can. Twice a day feeding your fish will help them to develop and stay plump. Your fish will learn when it's time to eat if you put them on a feeding routine, and they'll start eating closer to the place where you feed them from.  After some time, they'll get used to the feeding time and will eat directly from your hands!

What Are the Consequences of Overfeeding Your Koi?

Overfeeding can have a detrimental influence on the health of your koi and the water quality. When koi are overfed, they excrete more waste, which can lead to poor water quality and an increase in algae. So, when feeding your fish, keep the following in mind:

  • The ideal quantity of food will be consumed by the koi in 5-10 minutes.
  • Check for any leftover food in the water. Uneaten food will generate toxic ammonia and nitrite buildup.

  • Uneaten food emits nutrients that encourage algae to grow.

  • Sludge layers form as food remains are removed and dropped to the bottom of the tank.

  • Overfeeding results in disease outbreaks. A filthy pond is ideal for fish diseases.

  • Overfeeding may lead to obesity and strain the heart of your koi fish.

What Are the Best Koi Food for Growth and Color?

Increasing the color and growth of koi is one of the main objectives of feeding koi fish. Koi food companies have responded to this by formulating a variety of foods that are designed for color enhancement and growth.

When it comes to selecting the best type of koi food, you need to consider the dietary needs of your fish. Spirulina will improve the color of your koi and enhance their immunological function. This nutritional supplement improves the color of the koi's flesh (skin) and makes it more attractive. 

A koi diet should include wheat germ oil because it is a significant nutritional component. This will benefit the fish's general health and help it to reach its full size.

Why Is My Koi Not Eating? 

If your koi refuses to eat but you're unsure why don't worry! There are a few typical reasons why koi might not be hungry. These include:

  • Change in Water Temperature:
    If your koi's water temperature changes suddenly or becomes too hot, cold, or mild, it may cease eating. Don't be concerned as long as the temperature hasn't reached hazardous levels. The temperature will also fluctuate with the seasons and return to normal when the temperature is stable. The sudden drop in temperature of the water alone might cause koi to cease feeding.
  • Stress:
    If your koi become stressed, they may cease eating. This is normal and usually subsides after the stressful event has ended.
  • Digestive Problems:
    If your koi have a digestive problem, they might not feel like eating. Consult with an experienced koi keeper to get an accurate diagnosis and appropriate treatment.
  • Poor Water Quality:
    Poor water quality, such as high levels of ammonia and nitrite, can cause koi to stop eating.
  • Lack of Oxygen:
    Low dissolved oxygen levels in the water can also lead to a loss of appetite in koi.
  • Sickness and Parasites:
    If your koi are sick or have parasites, they might not feel like eating. Consult with an experienced koi keeper to get an accurate diagnosis and appropriate treatment.
  • Aging:
    As koi age, their appetites usually decline. So they may not eat as much as they used to.

If you've ruled out all of the above reasons and your koi still isn't eating, consult with an experienced koi keeper for help. They'll be able to tell you what might be wrong and how to get your fish eating again.

What Shouldn't You Feed Your Koi Fish?

There are a few things you should never feed your koi, including:

  • White bread
  • Beans as it is hard to digest
  • Peas as it is hard to digest
  • Processed food

What if Your Koi Won’t Eat? 

If your koi becomes a picky eater and refuses to eat, don't worry! There are a few things you can do to get them started again:

  • Try feeding them at different times of the day. Some koi are more active in the morning while others prefer to eat later in the day.
  • Offer different types of food. Some koi might not be hungry for their usual food, but they may be more inclined to eat a different type of food.
  • Try changing the location where you feed your koi. If they're used to eating at one spot in the pond, try moving the feeding area to a different spot.
  • Increase the water temperature. If the water temperature is too cool, try raising it a few degrees until the koi become hungry again.
  • Consult with an experienced koi keeper for help. They'll be able to tell you what might be wrong and how to get your fish eating again.
How Long Can Koi Fish Go Without Food

How Long Can Koi Fish Go Without Food?

Koi fish can go for extended periods of time without eating if they have access to food in their pond.

During the summer, a healthy koi can go for a whole week without feeding. As a result, if your koi appears to be bloated, don't hesitate to skip one day of feeding.

During the winter season, a koi might survive an entire season without eating if the temperature is too low. In fact, it is advised not to feed your fish at all if the temperature is less than 41 degrees Fahrenheit or colder.

Vacations and Koi Feeding

It's quite normal to leave the fish for a day or two. They'll search for live foods until you return. But what do you do if you are gone on a trip or away for an extended period of time?

If you have a trustworthy neighbor or family member, show them how to feed your fish before leaving home. Use a measuring cup or wrap each day's feeding in a plastic bag to make it easier for the person to feed the koi. This removes any uncertainty about how much to feed the fish, making it simple for them to do so.

Another alternative is an automated pond fish feeder, which can be programmed to feed your koi one or several times a day. Some pond feeders are so big that they need access to electricity. Smaller battery-operated versions are available for smaller ponds.

Final Thoughts: 

Koi fish will consume almost anything! They are omnivores and will consume a range of foods, including live food, flake food, pellets, and vegetables. For enhancing the color and growth of koi fish, it is important to give them a balanced diet that includes all the right nutrients. Protein and carbohydrates are required in the finest koi food. Flake, pellet, stick, and even powered formulations are available. 

If you're having trouble getting your koi to eat, don't worry! There are a few things you can do to get them started again. Consult with an experienced koi keeper for help. They'll be able to tell you what might be wrong and how to get your fish eating again.

Sarah Robertson

I am a passionate blogger who also happens to be a fish keeping enthusiast. Writing about my hobby is something that I absolutely love to do, and it's no secret that my chosen topic is always centered around fish keeping.

Sarah Robertson

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