Understand the Science Behind Feeding Koi: A Taste of Perfection

For many pond owners, having fish in the pond is the main reason for creating a water feature in the first place. Plenty of pond owners have been keeping aquarium fish for years and decide to expand their hobby to the outdoors. Others see fish as a beautiful addition to their water garden. No matter what your motive is for owning pond fish, you’ll enjoy this satisfying hobby for years to come. You might be surprised at the affinity you acquire for your fish and find them to be just as important as a pet dog or cat. You may even decide to name them. And just like your furry friends, your finned friends need a little special care and should be given proper nutrition to survive and thrive. Learn what you need to know about feeding koi and pond fish


To Feed or Not to Feed

Feeding koi is a fun activity that the whole family will enjoy. After you first bring your fish home, they’ll be a little shy and won’t seem interested in what you’re feeding them. Don’t worry too much about this; just sprinkle a little food in the pond and move back. After a few minutes, they’ll likely take interest in the food. Try to be consistent when feeding. Feed them at the same time from the same location and they’ll become conditioned to your visits.

Since everything you put into the pond is going to be broken down and removed by the filter, it’s important to remember to only feed your fish high quality food that is specifically designed for the fish in your pond. Feeding them low quality food can lead to water quality issues like green water, string algae, and poor water conditions.

Many pond owners also choose to offer their fish a treat now and again. If you want to do the same, try a little fresh watermelon and watch your fish go crazy. Other options include small orange slices like mandarin oranges, and Honey Nut Cheerios. Keep in mind that the natural ecosystem has to deal with every bit of food that’s not consumed and left in the pond. So, be careful not to overfeed.


father and son feeding koi

Five Minute Rule

A good rule of thumb is to only offer what your koi and other pond fish can eat in five minutes. The decision to feed your fish is up to you. Many pond owners never throw a single piece of food into their pond. Your pond will produce food for your fish to eat and also help create a balance between plants and fish. Remember, however, that larger fish need more food than small ones, so they may take a look at your plants for snacks if not fed enough. Not to mention, feeding koi and pond fish adds fun and enjoyment to Living the Aquascape Lifestyle®.


Choosing the Best Food

Studies have been done comparing the digestion of protein from various sources in fish and found that fish proteins were the best digested and assimilated by fish. Simply put, fish eat fish.

Fish are adapted to the consumption of others in their food chain, so fish proteins are the best choice of food. When you look at a bag of fish food, the first ingredient listed should be fish or other aquaculture proteins.


Are Plant Proteins Bad?

Plant proteins aren’t necessarily bad when feeding koi and pond fish. They provide other nutritional value such as fiber, plant protein, and carbohydrates (energy). Plant proteins shouldn’t replace aquaculture proteins, but when used in conjunction with each other, it’s beneficial because proteins in corn, soy, or wheat are very different from proteins in a feed ingredient like shrimp or blood meal. So, you might see fishmeal listed as the first ingredient, and then wheat germ, soybean meal, or corn gluten meal lower on the list. This is perfectly acceptable and nutritious.


Assessing an Ingredient Label

Ingredient labels can be very exciting, or very misleading. They can be exciting because they seem to report excellent ingredients and real care and attention in manufacturing. Misleading labels use techniques like ingredient-splitting and foreign laws to confuse the consumer. So let’s assess a label together in nine steps.

Protein source – Look for blood meal, fish meal, squid meal, shrimp meal, herring meal, or other aquaculture protein as first ingredients. These are the best protein sources for fish.

Purpose of plant material – If you find a food that has no aquaculture protein, but two plant proteins, then the manufacturer is trying to get less expensive plant ingredients to do what fishmeal should be doing. But, if you find a food with fishmeal as the first ingredient and then wheat germ or similar, they are using the plant ingredient for protein and energy, letting the fishmeal carry the bulk of the protein requirement, which is as it should be.

Protein percent – Because of the simplicity and shortness of the tract, koi can’t digest more than 32 to 36 percent protein in one pass. Feeding more than that isn’t necessarily a bad thing because fish will simply pass what they don’t digest – it’s just expensive to pay for it.

Fat content – Find a food with between three to ten percent crude fat. The high end of this range is good for smaller fish, and the lower end of the range is good for adult fish.

Ascorbic acid – Make sure ascorbic acid, or L-Ascorbyl-2-Phosphate is on the label among the trailing ingredients. It will represent a very small part of the diet, but it should be added to any milled food.

Immune boosters – Some foods are made with immune boosters. Look for any combination of the following supposed immune-boosting ingredients: optimum, aquagen, nucleotides, torula yeast, brewer’s yeast, bee propolis, colostrum, aspergillus niger, beta carotene, lactoferrin. These may perform as promised, and certainly don’t hurt, but don’t depend on any particular ingredient as a miracle supplement or lifesaver. Just recognize that the addition of these items represents the manufacturer as a little more attentive and knowledgeable, and the food worth a little extra money.

Color enhancers – Are there color enhancers in the diet? Look for terms like spirulina, bio-red, beta carotene, canthaxanthin, marigold petals, xanthins, shrimp oil, synthetic and non-synthetic carotenoids, or color enhancers on the label. Shrimp oil is the most expensive and performs well or better than synthetic carotenoids but is acceptable. Spirulina cannot push color unless the fish are exposed to sunlight and have the genetics for color. None of these color enhancers are hazardous to fish, but they can make a fish with a yellow head more yellow, or a fish with a tendency towards pink, pinker. No color enhancer can replace the irrefutable contribution of genetics and sunlight.

Ash content (if stated) – Some fish food manufacturers will tell you the “crap” content of their food. Ash is what’s left behind when you incinerate (or the fish digests) the food. It’s almost all carbon and mineral. So, the higher the ash content, the less likely one is to appreciate it. Generally, when ash is high, a smart label guy would just leave it off, and they are allowed to skip this information because it’s not required on fish food bags.


Because your finned friends live in a manmade water garden, they depend on you for proper nutrition and sustenance. Learning how to shop for the best quality food, the proper time to feed them, and what treats they enjoy can ensure your friends stay healthy and increase your enjoyment of your backyard pond. Now that you know the basics of feeding koi, you can enjoy your fish for many years to come.


Color Enhancing Koi Food