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

Find Out More On Koi Fish Diets So You Can Have Happy Ones In Your Maryland Pond
Feeding koi fish from out of your hand

You can feed koi vegetables, fish food, fruit, and pretty much anything that doesn’t have a lot of carbs. Feed them over a 5 minute period.

Discover more below-

It’ll Be Fin-tastic!

Christina sighs and rubs her temples after hearing that truly un-fin-tastic joke.

She loves Matt, but his jokes can be…yeah, well, anyway, back to the main issue: caring for the koi fish they’re about to buy.

“We have the pond, and it’s an ecosystem pond too. That means we don’t need to feed them for survival, just for fun,” points out Matt. Christina nods. “True, now we just need to know what can koi fish eat, how to feed koi fish, and what we shouldn’t feed koi fish.”

“Let’s look it up!” booms Matt as he gets his phone. Christina laughs, saying “That’s the spirit! I’ll do the same and we can talk about what we find on Google. Hopefully, we can also find out how long pond fish can live for.”

Here are the answers they find:

General Information On Feeding Koi Fish

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

What do koi fish eat infographic

If you have an ecosystem pond 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 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.

Koi fish under ice is fine because winter pond maintenance was performed

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.

What Koi Fish Eat Naturally

Koi fish ready to eat

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.

There are 4 main foods people feed koi fish:

1. Spirulina Algae

Spirulina Algae tablets are good to feed koi fish

These blue-green algae, also called cyanobacterium, live in water and make their own food. They’re very small, only growing up to half a millimeter in length. This algae is free-floating and can be found in lakes with an extremely high pH and very hard water.

Feed koi fish spirulina algae for these benefits:

  • Higher growth rate
  • Improving digestion
  • Boosting the immune system
  • Helping prevent swollen abdomens
  • Enhancing the production of special enzymes that break down fats into energy
  • Bringing out better coloration due to carotene pigments found in the algae

2. Wheat Germ

Wheat germ is great for feeding koi fish

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 wheat germ can help goldfish and koi grow faster. It’s also a natural source of vitamin E which improves blood circulation, increases oxygen and nutrient flow, helps promote balanced growth, and aids in fighting off disease.

3. Brine Shrimp

Brine shrimp filter water and feed fish

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 for feeding recently hatched koi fish.

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 fish 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.

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.

Playing with koi fish while feeding them

Don’t feed them anything you catch in the wild either. This includes fish, bugs, frogs, and everything else. They could have parasites or diseases.

Grains aren’t the best food for koi. 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.

Of course, these foods should not be the basis for their diet. They have little nutritional value for koi.

How To Feed Koi Fish

Grandfather and grandson feeding koi fish by hand

Cut up any larger foods into bite-sized pieces. Toss one handful into the pond. Let the koi eat as much as you can see before the next handful. Any food left in the pond needs removing. This way it doesn’t break down and lower the water quality.

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“This is great! Now we know how to feed our fish and stuff,” says Matt happily. Christina smiles. “That’s true! Now, let’s see what else this blog has to say on caring for koi fish.”