What Do Koi Fish Eat, Can’t Eat, And How To Feed Them

What Do Koi Eat?


Not sure what to feed your koi fish? You’re not alone. Koi fish food can be confusing, but it’s important to get it right. In this blog post, we’ll break down the question of “what do koi fish eat” and give you advice on how to provide them with the best possible diet. This way, they can live as long as they’re supposed to (along with regular pond maintenance and pond cleanings in Maryland).

So, whether you’re a first-time koi owner or just looking for some clarification, read on for everything you need to know about feeding koi fish.

General Information On Feeding Koi Fish

Here’s almost everything you need to know on how to feed koi fish:

Photo from https://landscapingbychuck.com/what-do-koi-fish-eat

Feeding koi fish is different if you have an ecosystem pond. You don’t have to feed them as often because they will eat insects, parts of plants, and everything else they can find.

If you don’t have plants, you can feed koi fish as much as they can eat in 5 minutes once per day.

Fish don’t have the ability to tell when they’re full, so they won’t stop eating as long as there’s food to be had.

The best time to feed your fish is when the pond water is between 50 degrees and 85 degrees Fahrenheit because outside of this range, they can’t digest very well. During winter, they hibernate, so please do not feed them.

Also, get food pellets appropriate for the size of your fish. A better-suited size means your fish can digest more efficiently, making for healthier fish that can grow to their proper size.

Koi Fish Food Quality

What you feed your fish will have a big impact on their health and well-being. That’s why it’s so important to choose the best koi food over low-quality options.

High-Quality Koi Fish Food

High-quality koi fish food is made with fresh ingredients that are rich in nutrients.

This type of food is typically more expensive than its low-quality counterpart, but it’s worth the investment because it will help keep your koi healthy and vibrant.

High-quality koi food should also be slow-sinking, so your fish have to work a little harder to eat it. This helps ensure they’re getting the exercise they need to stay healthy.

Low-Quality Koi Fish Food

Low-quality koi fish food is made with cheaper ingredients.

This type of food can cause health problems for your koi, making it likely that they won’t live as long as fish on a high-quality diet.

Low-quality koi food typically sinks more quickly, meaning your fish don’t have to work as hard to eat it. This can lead to obesity, which can shorten their lifespan.

What Do Koi Fish Eat Naturally


In the wild, koi fish eat algae, plants, insects, worms, seeds, and anything they can stir up from the pond’s bottom.

They hunt along the pond floor and along the surface. If you have an ecosystem pond, they can continue having their natural diet.

This means feeding time is simply a way to bond and have fun with your fish.

What You Can Feed Koi Fish

You can feed koi almost anything people can eat.

This includes shrimp, fruit, vegetables, and anything that isn’t high in carbohydrates. Bread and foods like that are hard on your fish’s stomachs.

You can also feed them fish food pellets. Make sure they’re the right size.

Types Of Koi Food

Understanding the different types of koi food available can help you provide a balanced diet:

  • Prepared Foods: Pellets are the most convenient and commonly used koi food, formulated to meet all nutritional needs. They come in floating and sinking varieties, with floating pellets preferred for observing feeding behavior and preventing overfeeding.
  • Fresh and Freeze-Dried Foods: Supplement your koi’s diet with fresh foods like chopped vegetables, fruits, and proteins such as shrimp. Freeze-dried blood worms and brine shrimp can also provide additional nutrients.
  • Seasonal Foods: Adjust your feeding strategy with seasonal foods. In colder months, opt for easily digestible options like wheat germ pellets. During warmer months, high-protein foods will support your koi’s growth and vitality.

The Best Koi Fish Food

The best answer to “What do koi fish eat?” is high-quality food. The fewer processed ingredients it has, the better it is for your pond fish.

You’ll also want to make sure your koi have a balanced diet, which can include the following foods:

1. Spirulina Algae


These blue-green algae, also called cyanobacterium, are very small, only growing up to half a millimeter in length. It’s free-floating and can be found in lakes with extremely high pH and very hard water. You can find this koi fish food in pellet form.

Koi fish eat algae for these benefits:

  • Higher growth rate
  • Improved digestion
  • Boosted immune system
  • Prevention of swollen abdomens
  • Enhanced production of special enzymes that break down fats into energy
  • Bring out better coloration due to carotene pigments found in the algae

2. Wheat Germ


Don’t worry; it’s not the bad kind of germ. This is the part of wheat that sprouts and grows into a new plant, the wheat seed, if you will. Experiments have shown that eating this pond fish food can help goldfish and koi grow faster. It’s also a natural source of vitamin E, which improves blood circulation, increases oxygen flow, increases nutrient flow, helps promote balanced growth, and aids in fighting off disease.

Feed your koi this type of koi fish food for these other benefits:

  • Higher growth rate
  • Better overall health
  • Brighter color scales
  • Improved digestion

3. Brine Shrimp


Here’s a fancy science word for you: bio-enrichment. Brine shrimp filter water by eating anything in it they can, which isn’t much due to their small size. The nutrients they eat pass on to the fish they are eaten by, which is the process known as bio-enrichment. Brine shrimp are especially good koi food for recently hatched koi fish.

This type of koi fish food will bring these benefits to your koi:

  • Protein, vitamin A, and vitamin D
  • Higher growth rate

4. Fish Food

Small and baby koi prefer flake fish food, the smallest form. Pellets are good for the average-size koi, while larger koi prefer bars of koi food. Most have plenty of proteins, a small number of fats, and essential vitamins & nutrients. Some other favorites include worms, larvae, tadpoles, shrimp, and clams.

5. Hi Silk 21

This is one of the best koi foods on the market. It’s developed specifically to help koi fish grow well and stay healthy. Many champion koi eat this food, especially Nishikigoi, because it helps their white scales sparkle brighter.

Here are the benefits of this type of koi fish food:

  • High growth rate
  • Brighter white scales
  • Protein, vitamins, and minerals

6. Manda Fu

Manda Fu is a treat for koi made by fermenting high-quality fruits and plants, and they love it! Not only does it taste good to them, but it’s good for them too.

You can give your koi these benefits by feeding them this type of koi fish food:

  • Higher growth rate
  • Brighter colors
  • Better overall health

7. Some Human Food

You can feed koi almost anything people can eat. This includes shrimp, fruit, vegetables, and anything that isn’t high in carbohydrates. Like with humans, the quality of food you feed them will affect their health. Healthier foods will lead to healthy koi.

What Not To Feed Koi Fish


Don’t feed koi fish anything high in carbohydrates. You should also avoid feeding them white bread, peas, and corn. Koi fish have a hard time digesting carbs.

Koi fish food shouldn’t include anything you catch in the wild, either. This includes fish, bugs, frogs, and everything else. They could have parasites or diseases they can pass on to your fish.

Grains aren’t the best koi food. They tend to be very fattening, which is good if your fish start losing weight. If you decide to feed them pasta or rice, you’ll need to cook them without salt first. Otherwise, the food could expand inside your koi. These foods should not be the basis for their diet. They have little nutritional value for koi.

Some people feed dog food and cat food to their koi. We’d recommend being very cautious about this as it isn’t formulated for koi or a part of their natural diet.

For the price of koi fish, it’s best to feed them right and feed them well.

What Influences A Koi Fish’s Diet

Feeding koi carp by hand

Koi Fish Digestive Systems

Koi fish don’t have stomachs, so unlike people, they need to eat smaller amounts of koi fish food more often. Since they don’t have stomachs, they tend to fill up more quickly, hence why they eat smaller amounts of koi food more frequently.

Factors For How Much And How Often To Feed Koi Fish

  • Size: Smaller koi need less food, while larger koi need more food.
  • Seasonality: In the spring and summer, when water temperatures are warm, koi are more active and need more food to support their growth. In the fall and winter, koi become less active and require less or no food. As a result, koi keepers must adjust their feeding schedules accordingly. You can feed koi cold fish food at certain temperatures.
  • Temperature: Koi are cold-water fish, which means they do best in temperatures between 65 and 75 degrees Fahrenheit. They can survive in colder temperatures, but their activity and metabolism slow down, so they don’t eat as much. You can switch to cold water koi fish food when temperatures drop below 65. Koi will also stop eating when the temperature drops below 50 degrees and go into hibernation at around 40 degrees.
  • Water Oxygen Levels: Koi fish need dissolved oxygen to properly digest their food. So, when dissolved oxygen levels change due to a storm, koi fish can’t digest their food as well. It’s best not to feed them during or after a storm.
  • Water Quality: The more koi fish eat, the more fish waste they produce, meaning your water quality can decrease. This leads to lower oxygen levels, which strains their digestive tract. Keep your water quality at higher levels to make sure your koi stay healthy.
  • Pond Pumps: If your pond pump isn’t strong enough or fails, this can also lead to lower oxygen levels in your water, which stresses your koi fish.
  • Pond Type: Koi can find more food to eat in ecosystem ponds than in other manmade ponds. This means you’ll need to feed them less koi fish food, so they don’t eat too much and get fat or sick.

How Much Koi Food Should I Feed My Fish?

In ecosystem ponds, you’ll only want to feed your fish a handful of food twice per week. Any more and they can start having health problems.

If you don’t have an ecosystem pond, you can feed koi fish as much as they can eat in 5 minutes once per day. Over and underfeeding them can lead to health issues or hiding on the pond bottom.

How To Feed Koi Fish

  1. Cut up any larger bits of koi fish food into bite-sized pieces
  2. Toss one handful into the pond
  3. Let the koi eat as much as you can see before the next handful
  4. Any food left in the pond needs to be removed. This way, it doesn’t break down and lower the water quality.

Koi Feeding Tips

Feed Up to Four Times Daily: Koi can be fed up to four times a day. Each feeding session should last about five minutes, giving them enough time to consume the food without overeating.

Avoid Feeding Before Storms: Low atmospheric pressure during storms can reduce oxygen levels in the water, making it harder for koi to digest food. Pause feeding before a storm to prevent stress and health issues.

Bonding Through Feeding: Use feeding time as an opportunity to bond with your koi. They can recognize the person feeding them and may even eat from your hand, creating a memorable experience for both of you.

Use the Right Technique: Experiment with different feeding techniques. Scatter food across the surface to encourage active swimming, or hold food in your hand to foster trust and closeness.

Seasonal Feeding Guidelines

Koi have different dietary needs throughout the year, influenced by water temperature and their metabolic rate:

  • Spring and Fall: Focus on carbohydrate-rich foods to provide energy for temperature transitions. Wheat germ-based foods are ideal as they are easy to digest.
  • Summer: Increase protein intake to support growth and reproductive activities. High-protein foods like specially formulated koi pellets and natural options like brine shrimp will ensure your koi are well-nourished.
  • Winter: Koi enter a state of semi-hibernation and stop eating when water temperatures fall below 50°F. Ensure no food is offered during this period to prevent health issues.

Temperature And Koi Fish Feeding


You don’t want to feed them when temperatures drop below 50 degrees Fahrenheit. Their digestive systems slow down, so any food they eat may stay in their system until temperatures rise. This can make them extremely sick. There are more actions you can take to help your koi fish survive winter.

Koi Fish Food Automatic Feeders

Automatic koi fish feeders are devices that dispense koi food at regular intervals. They can be programmed to dispense food multiple times per day, and some models can even be set to dispense different amounts of food at different times of the day.

There are two main types of automatic koi fish feeders: those that use pellets and those that use flakes. Pellet-type feeders are more common, as they tend to be less messy and easier to use. Flake-type feeders are less common, but they do have their benefits; for example, some types of koi prefer flakes over pellets.

Automatic koi fish food dispensers can be an invaluable tool. Koi like being fed at the same times of day, much like people. You can set auto feeders to help ensure a regular feeding schedule.

Pros And Cons Of Koi Food Auto Feeders


Automatic koi fish feeders have several advantages.

  • They make it easy to keep your koi fed on a regular schedule.
  • They can help you keep your fish healthier by preventing over and underfeeding.
  • Also, they can be helpful if you’re going on vacation or otherwise away from home for an extended period of time.


There are also a few disadvantages to using automatic koi food feeders.

  • One is that they can be expensive. Depending on the model, an automatic koi fish feeder can cost anywhere from $50 to $200.
  • They also require regular maintenance. The dispenser must be refilled with food regularly, and the unit must be cleaned periodically to prevent mold and mildew build-up.
  • Automatic koi fish food feeders can be unreliable. If the unit malfunctions, your koi could go without food for an extended period of time. You can get solar ones to help prevent this, but cloudy and stormy days can disrupt them.

How Auto Feeders Work

Automatic koi food feeders typically consist of three main parts: a hopper or reservoir, a timer, and a dispensing mechanism. Most automatic feeders will also have some sort of built-in battery backup in case of power outages.

The hopper is where you’ll store the koi fish food pellets. The hopper should be big enough to hold enough food for several days’ worth of feeding, so you don’t have to worry about refilling it too often. Some hoppers also have built-in filters to keep debris and uneaten food from clogging up the dispensing mechanism.

The timer is what controls when the koi food is dispensed. Most automatic koi fish feeders will allow you to set different dispensing schedules for different days of the week, so you can customize the feeding schedule to fit your needs. 

The dispensing mechanism is what actually gets the koi fish food from the hopper into the water. Some automatic koi fish feeders use an auger or screw-like device to move the food from the hopper into a small opening at the bottom of the unit. The food then falls into the water below. Other automatic koi fish feeders use a vibrating plate or disk to move the food from the hopper into a chute that leads directly into the water.

Keep Your Pond At Its Best So Your Koi Fish Can Be Healthy And Happy With Premier Ponds

Premier Ponds is here to help you keep your pond healthy and looking great, so your pond fish can be happy and thrive. We offer a variety of pond cleaning and maintenance services that are designed for koi ponds. We also know how to introduce koi to ponds in a stress-free manner.

If you’re interested in learning more about our services, fill out our contact form today. We look forward to hearing from you soon!

*Quick tip: your koi fish will be better off if you add the right amount of koi for your pond size.