What Do I Feed My Koi?

Instead of the standard, “we tell you to buy this food,” we’re going to give you the tools to take ANY bag of koi food and decide if it’s “good” or “bad.” And what you think is “good,” may not be the same as what your neighbors think is “good,” and that’s okay!

Starting point: price point has absolutely nothing to do with quality. More expensive food is not necessarily better for your fish.

Step 1: Ignore the flashy marketing

It’s hard to ignore snappy slogans and the promise of “nucleotides,” but try your hardest to ignore everything on the bag of koi food other than the ingredient list and nutrient breakdown. Look at a picture on their website devoid of anything colorful if it helps.

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Step 2: Focus on protein

The primary nutrient requirement for koi is protein. But first, you have to decide the fate of your koi: are they going to show or breed, or are they going to hang out and live a lazy life? A show or breeding koi has a higher protein requirement compared to most backyard koi. For show koi, you are looking at a protein % of roughly 38-40%. Really big koi, trying to conserve a larger muscle mass, may be up to 42%, but that’s pushing it.

Now, the hard part. Count the total number of protein sources in the diet. In order to make a “complete” diet containing all the essential amino acids, it takes combining multiple protein sources. This may take a little extra sleuthing on your part and picking up on some funky scientific names. The more protein sources, the cheaper they are to add. Be especially wary of any foods adding “L-amino acid.” This is the super cheap method of a “complete” diet where they don’t even use an actual protein source, just a cheap synthetic.

Foods with lots of protein sources should be your cheaper options. They are not “bad,” but beware of a expensive food with lots of protein sources. We recommend comparing different brands by dividing the price per ounce per number of protein sources (example down below!).

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Step 3: Fight the fat

Across the spectrum of fish activity, koi are mostly sedentary. They are lazy, cruise-controlling fish who do not have high demands for fat reserves. You can cause obesity in koi by feeding them high fat food. Keep it under 5% for adult koi and 7% for juveniles.

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Step 4: Your fish don’t need fiber

Fiber is a great dietary additive if you have the digestion to process it. Koi do not have a “true” or acidic stomach and rely on their big molars to grind up their dinner and passive dietary absorption. This makes it hard to process lots of fiber. Your koi’s food should have less than 7% fiber so it isn’t just going in and directly out.

Step 5: No need to carbo load

Most carbs are added to koi foods for color enhancing. Remember, these only work if your fish have the underlying genetics to support it! Koi do not do well with high carb diets and can actually have liver issues at higher levels. This is why you should limit your carb rich treats, like watermelon, to only once a week at appropriate temperatures.

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Okay, that was a lot of information, so let’s take an example:

Example: Our Favorite Koi Food

Analysis:

Crude ProteinNot less than 35.0%
Crude FatNot less than 4.0%
Crude FiberNot more than 4.0%
AshNot more than 8.9%
Ash = vitamins and minerals, not sawdust

So, all of these are within our acceptable parameters for a good koi diet, so let’s look at the ingredients:

White Fish Meal, Wheat Flour, Ground Wheat, Corn Gluten Meal, Fish Oil, Lecithin, Shrimp Meal, Spirulina, Mono-Dicalcium Phosphate, Dried Saccharomyces cerevisiae, Propionic Acid (a preservative), Lignin Sulfonate, Mannan Oligosaccharides, Marigold Extract, Choline Chloride, Taurine, Canthaxanthin, Vitamin C (AsPP L-ascorbyl-2-polyphosphate), Zinc Proteinate, Manganese Proteinate, Copper Proteinate, Cobalt Proteinate, Ferrous Sulfate, D-Alpha Tocopherol Acetate, Zinc Sulfate, Magnesium Oxide, Yucca Schidigera Extract, Niacin Supplement, D-Calcium Pantothenate, Copper Sulfate, Vitamin K(Menadione Sodium Bisulfite Complex), Thiamine Mononitrate, Riboflavin Supplement, Pyridoxine Hydrochloride, Vitamin A Acetate, Vitamin D Supplement, Biotin Supplement, Selenium Yeast, Vitamin B12 Supplement, Folic Acid, Cobalt Carbonate.

We’ll make this easy and divide these up into their appropriate nutrients (note: some foods will be labeled with vitamin/mineral premix, which is fine and perfectly legal. This one decided to add individual additives):

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ProteinFatCarbohydratesVitaminsMinerals
– White Fish Meal
– Wheat Flour
– Ground Wheat
– Corn Gluten Meal
– Shrimp Meal
– Spirulina
– Taurine
– Fish Oil
– Lecithin
– Propionic Acid
– Spirulina – color-enhancing
– Dried Saccharomyces cerevisiae – probiotic
– Lignin Sulfonate
– Mannan Oligosaccharides – probiotic
– Marigold Extract – probiotic
– Canthaxanthin – color-enhancing
– Yucca Schidigera Extract – probiotic

– Vitamin C
– D-Alpha Tocopherol Acetate
– Niacin Supplement
– Vitamin K (Menadione Sodium Bisulfite Complex)
– Thiamine Mononitrate
– Riboflavin Supplement
– Pyridoxine Hydrochloride
– Vitamin A Acetate
– Vitamin D Supplement
– Biotin Supplement
– Vitamin B12 Supplement
– Folic Acid
– Mono-Dicalcium Phosphate
– Choline Chloride
– Zinc Proteinate
– Copper Proteinate
– Cobalt Proteinate
– Ferrous Sulfate
– Zinc Sulfate
– Magnesium Oxid
– D-Calcium Pantothenate
– Copper Sulfate
– Selenium Yeast
– Colbalt Carbonate
Fish can easily digest corn and there has NEVER been a gluten-intolerant or vegetarian koi, just education-intolerant owners.

Well, that made my brain hurt. Several of these ingredients do not fit into just one category. Let’s count our protein sources: 7. Yes, there is one pure amino acid, taurine, but it is not essential and likely supplemented since white fish meal does not have a lot. Is this a lot of proteins? Well, we looked at 4 other similar koi foods and found the following: 7, 12, 8 and 11. So 7 protein sources is on the lower end. Again, this does not make it “better,” but it means they use higher quality, more “complete” ingredients.

Now, a 22 lb bag of this food sells for $129.98, or roughly $5.90/lb. Again, they are using a higher quality ingredients, so you should expect it to be more expensive. In comparison, our koi food with 12 protein sources sells for $5.66/lb and 11 protein sources $3.20/lb. What do you get for an additional 5 protein sources of inferior quality? Marketing! Yes, that’s really all it is.

So, in conclusion, it’s up to you entirely what you feed your koi. But, if you have some free time, do your research and you might be surprised that the “high quality” food you are feeding your koi might be all marketing.

I don’t want to do all these calculations! If they were your koi, what would you feed?

Here’s our favorite! High quality ingredients, nutritionist consults, probiotics and made in California!

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