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Feeding Koi

Koi Food

Feeding Koi can be very enjoyable. They are easy to tame and will feed from your hand. Koi are omnivorous feeders, which is to say they will eat foods of both plant and animal origin. Anything you will eat you can assume a Koi will too.

Food is taken in through the mouth and is broken up by the pharyngeal teeth. The process of digestion begins as food passes through the fish’s digestive juices. The long intestines help to digest fibrous plant material and enable the fish to dispose of indigestible material through the vent.

Because Koi have no stomachs as such they cannot eat large amounts of food at a time because they cannot store it like we do. They are thus constantly browsing and eating, foraging around steadily. However, in the pond there is not as much natural food as in a river so they will eat greedily for very short periods. A little and often is better than two large meals, but for many people their work dictates that feeding can only be done twice per day, once in the morning and once in the evening, but this is not recommended.

Koi are cold-blooded animals that should not be fed when the temperature falls below 55° F. Their need for food is greatly reduced and correspondingly, so is the rate of digestion. At the ideal temperature of 70-75°F, Koi can consume approximately 2-3% of their body weight in food/day; the correct amount of food is that which is consumed in 10 minutes. After feeding if any food is still left in the water you have feed to much, try to net it out.

If you want to make a friend of each Koi you own, then you must feed it personally and not just throw the food into the pond. Feeding is not only a metabolic process but it is also a social activity that creates bonds between the fish community itself and with us humans.

For Vitamin and Mineral Deficiencies, Good Sources of Vitamin C, and How to Make Paste Food Click Here.

Feeding for Color Enhancment

Koi are highly valued for their color and certain additives can be included in the diet to maintain and enhance the fish's natural coloration.

Carotene affects the red pigmentation, but if used at too high a concentration, even the white pigment on the Koi will turn pink. Spirulina platensis also enhances and fixes the red pigment, but does not turn the white to pink to the same extent. It is a type of algae found and cultured in Mexico and eaten by the people, since it contains a high level of protein. Initially, it was fed to Koi on account of its nutritional value and not because of its colour-enhancing characteristics. Now that these have been established, it is fed to koi for only one month each year, usually during September, but can be given at any time. Some koi farmers feed it for the month before the fish go to market to bring out the best colours in the Koi. Good coloration is not only enhanced by good feeding, however. Healthy fish tend to have much brighter colors than diseased ones.

To bring out the color in Koi, particularly the white, you must provide good living conditions. Strong red and yellow pigments develop well in waters rich in green phytoplankton (single-celled plant). Because Koi are difficult to see in green water, it helps to feed a diet that will enhance the red pigmentation. Black pigment is enriched in hard water with a pH level of 7.5-8.5. Remember, however, that changing the pH and hardness of the water can affect the toxicity of ammonia and nitrite. Color is created by pigments and these are produced from amino acids which are derived from the food. Certain foods contain natural coloring agents in greater amounts than others, so that if these former foods are fed then the Koi will develop better color. However, in excess, these foods will also produce an over abundance of pigment and this will spoil the colors.

When feeding Koi for color enhancment look for terms like Spirulina, Bio-Red, BetaCarotene, Canthaxanthin, Marigold petals, Xanthins, Shrimp Oil, Synthetic and Non Synthetic Carotenoids and Color Enhancers on the labels of the Koi food.

Feeding Koi Carp for color is known as iroage in Japan (bringing out color) and breeders have used it with great skill. Color feeding will not, however, put color where it does not already exist.

Koi Food

Balanced Diet

When feeding you need to make sure they are getting a balanced diet. There are a wide variety of Koi foods available. They are commonly found in stick, pellet and flake forms, with the stick variety being the type of food normally preferred for an average pond.

Food sticks tend to float initially and then sink as they soak up water. Good quality sticks will not break up too quickly and will therefore allow feeding at all levels in the pond to obtain a regular source of food. A good, balanced food will contain all the ingredients required for fish to grow and remain healthy. To supplement the dry foods add some fresh veggies. Holistic Select Koi Food has veggies and fruits. A Koi's gut is more suited for grazing on low concentrated foods like algae, sticks, weeds an occasional worm, crayfish, and snails.

Koi need to eat vegetables to compliment the pellets so they get their living enzymes, the right antioxidants, the living food, and the vitamin C that they're only going to get from eating vegetables. Koi love broccoli! You can cut the Broccoli florets up and toss them in the water, these will float on the surface of your pond.

When buying food you want to get a good quality pellet that doesn't have a lot of corn in it, because the corn diets tend to dirty the pond more. It goes through the fish more quickly and tends to dirty the filter. This will put a larger load on your filter.

Nutrition, long term nutrition is very, very important! You don't want the fish too fat, and you don't want them too skinny. You also don't want them to live on a diet of strickly pellets.

Feeding Guidelines for Water Temperature

Water temperature is extremely important for feeding Koi because the Koi is actually more of a warm water fish. The preferred temperature for Koi is around 72° or 76° F. At that temperature, they are able to digest their food very well. June, July, August, and September are when the temperatures are actually favorable for the fishes digestive system.

During the summer months Koi can really pack on the weight. They put on their growth during the summer so when the water temperature gets down below 55° to 50° F you can stop feeding them. During the winter months you won't feed them anything, they will be on a winter fast for several months. This gives the fish an opportunity to live off of its fat reserves that he gained in the summer. It gives the Koi's liver a chance to clean out any excess fat, so he doesn't have a fatty liver degeneration. By taking the fish off their food, they will clean up and actually have fresher looking skin and healthier colors.

It also allows older female Koi to use up some of their leftover eggs from the previous year. A female Koi will sometime snot expel all their eggs. They'll carry them on into the next winter or the next spring. They can get too heavy with eggs. They can actually become impacted and have trouble, so you want those females to use up their eggs.

During the winter fast, they lose some of their enzymes for digestion, so we have to slowly give them easy to digest food like wheat germ food or grains like Cheerios or oatmeal or brown cooked rice, foods that are easy to digest. Not a high protein. They can always eat fresh vegetables. When your water temperatures start to warm up and stay at 55° F, for a full 10 days, you can gradually increase their food level, so that they can get accustomed to eating food again.

You slowly bring them back to a regular eating schedule over a couple of months through spring. Spring is a very sensitive time for Koi. A lot of problems Koi experience in the spring is simply because they ate too much in the winter and the spring.

We love to feed our Koi and I know it's hard to resist when they are begging, but in the long run they will thank you. They don't have the same kind of digestive system or metabolism as we do. And, as we start increasing their food through late spring, maybe even onto May or June, then temperatures are now approaching your 65, 70 water temperature. Now, the fish can start actually digesting larger quantities of food. You have to gradually build them up so that in those warmer months, you could literally feed your Koi eight times a day (remember to only feed what they will eat in 5 minutes). The reason you can now feed them so many times is because they can now digest it, and this is when your fish will grow.

So all through the summer months, even through September, if it's warm, you can really pound them up with the food. They gain their weight, they put on their growth, and that's the true way of keeping Koi healthy long-term, from a nutrition standpoint.

There have been experiments made where Koi that were fed all year were compared to Koi that were fed only heavily in the summer and not at all in the winter. At the end of the summer, both fish had grown the same. The Koi that had been taken off the food in the winter actually had fewer problems, had experienced less disease problems, had better skin quality, brighter colors and, in some cases, actually grew bigger.

Even if you live in a warmer climate you should still put your Koi on a winter fast, even if it's only for just a month. It will give them an opportunity to use up some of their fat.

Live Foods

The range of live foods that a Koi will enjoy is considerable and a few of the more popular options are given here.

Buy your live foods from your pet shop or Koi dealer. There are companies that breed worms, daphnia, and maggots. Some import or breed locusts and flies and these can be purchased live or freeze dried so they will store for long periods which means they will be fresh when feeding Koi.

You can have deep frozen foods as well so it really is not worth bothering with wild caught foods.

Earthworms, *Tubifex Worms, Bloodworms and Glass worms These are relished by Koi but must always be clean and well washed.
Daphnia These are long time favorites of aquarists and are essential for baby fry that are recently hatched. You can buy daphnia cultures and breed your own or simply buy them from pet shops.
Water Lice are not like house lice but live in ponds and rivers even in pond filters. Small Koi cannot cope with their stiff outer shell but large Koi have no trouble eating them.
Mosquito Larvae These are small insects that swim on the surface of ponds. If you have plants in your pond, then you will attract these and many other insects which the Koi will catch at or just below the water surface.
Maggots These are the larvae of various flies. Their actual nutritional value is not especially high but the Koi enjoy them in moderation. Do not feed those which heave been treated with color dyes for anglers as the dye may be toxic, if not in the short-term then by long-term build-up if regularly used.
Tadpoles The tadpoles of frogs, though not of toads, will be taken by Koi. You should not take frog spawn from natural ponds. Apart from the fact that many frogs are now endangered, and thus protected, species, you could introduce unwanted parasites and disease organisms. If frogs should perchance enter you pond then so be it, the Koi will eat the hatching youngsters; I would remove the frogs and place them in a natural environment. Frogs are not a problem to Koi and may actually be beneficial around a pond in taking insects that are not wanted in the pond.
Shrimp These are tiny crustaceans and are much relished and will help bring good color to your Koi. So will many other small crustaceans.
Grasshoppers and Locusts Small examples of these insects are now bred on a large scale because they are popular with reptile keepers. Your Koi will enjoy them too-and flies. Never feed flies that have been killed with insecticides; swat them.
Infusoria This is a collective name for many microscopic organisms found in sunlit waters. They are the first foods eaten by baby Koi and you can produce cultures of them if you wish to but this is not necessary with Koi kept in hatcheries as these micro-organisms will colonize the water anyway.

*Live tubifex worms may carry bacteria and other organisms harmful to fish, especially captive fishes under stress. Be sure of your source and keep them in a gentle flow of cool running water or else they will die and decompose rapidly.

In the wild, Koi are omnivores that graze. Small amount of feed containing plant/fiber content will simulate a more natural diet, although in some ponds, there are plants, algae and bugs on which to graze. Crustaceans, such as krill, brine shrimp (Artemia), or water fleas (Daphnia) can have a laxative effect in fish. If a koi is constipated (which is seen as a long fecal trail attached to the anus), then some of these crustaceans added to the feed may alleviate the constipation.

Feeding rates, based on water temperature, for growth or maintenance rations.

Water Temperature (°F) Growth Ration (%body weight/day) Maintenance ration (%body weight/day)

Fish Less than 1/2 Pound

>90° 1.0 0
70-90° 3.0 1.0
60-69° 2.0 0.5
50-59° 1.0 0.2
45-49° 0.5 0
<45° 0 0

Fish More than 1/2 Pound

>90° 1.5 0
70-90° 3.0 1.0
60-69° 2.5 0.7
50-59° 1.0 0.5
45-49° 0.5 0.2
<45° 0 0

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Amount to Feed

As a general guide when feeding Koi, other than that given to them by hand, your Koi should be given only that which they will consume during a five minute period.

You should always have the time to spend feeding your Koi-that is staying with them while they feed. This way you will know if you have given them enough or too much, and by knowing their daily habits you will not be wasting food that will fall to the pond bottom and decay. Koi will not eat decaying food, so if they do not eat it at feeding time it will be ignored thereafter. You should try and get out any left over food for your Pond health.

At different times of the year, fish eat for different purposes. They will eat more when preparing for reproduction then they do in maintaining health and growh. After they spawn, they no longer need massive amounts of food, even though they certainly can comsume it within the five minutes. There are two things NOT to sacrifice when caring for Koi: nutrition and water quality. Less is more when feeding your Koi. Feeding heavily will not make the fish grow faster, bigger, or stronger. However, proper feeding and proper nutrition are the keys to success in preventing illness and raising larger, more beautiful, and healthier fish.

If you know your Koi’s diet individually, you will quickly notice if any do not turn up when the time for feeding Koi has arrived and this could mean it is ill or missing. For your Koi health this is important. Any that do not feed as normal may be showing the first signs of illness, this is one reason it is important to watch while feeding your Koi.

If you do not have the time to watch your Koi, then you have too many. To put weight and size on your Koi, they must be constantly fed. Compare the food values of the Koi food you are buying. Select the most nutritious one.


Koi need vitamins just as we do; in fact they may need more in ration to their size than we do because their metabolism is less efficient. If you give a good varied diet when feeding, vitamin supplements will not be required and may be harmful because they will create chemical imbalance in the cells and this can negate the benefits of other vitamins. If in doubt discuss the matter with a vet-preferable one who is familiar with fish.

Vitamins are found in all foods in different proportions which again suggest that if the diet is varied there will be no problems.

Various minerals and other chemicals are needed by the Koi in very tiny amounts; minerals are found in all foods and of course they are in the water as well.

Amino Acids

Amino acids help Koi grow, reproduce and maintain good health. Koi need 10 amino acids, arginine, phenylalanine, histidine, isoleucine, leucine, lysine, methionine, threonine, tryptophan and valine, supplied to them via their diets because their bodies cannot make these.

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