How to Take Care of Your Koi Fish

There are many different varieties of koi fish varying in color, size, pattern, and type of scales. It makes them one of the most beautiful pond fish available. Thanks to their popularity, you can now find them in ponds worldwide. But apart from being excited, you must take some precautions as well. Our article on koi fish care will help you take the necessary measures to keep your koi fish safe. 

Overview of Koi Fish

You must have a basic knowledge about these fish before keeping them in your pond. Koi fish are ornamental variations of the common carp (Cyprinus carpio). They belong to the Cyprinidae family, which involves all carps and minnows. ‘Koi’ originates from the Japanese word for carp. 

aquarium koi fish

Japan started keeping and breeding koi in the 19th century. During this time, the farmers used to keep the native carp’s colorful specimens in their rice gardens. Considering their popularity in the past century, keeping and breeding these fish is a widespread and lucrative industry.

Koi Fish Behavior 

Koi fish are very peaceful and interact with the others in their school. They build schools of anywhere between 5 and 15 fish and swim in elegantly coordinated formations. They swim in every level of your pond while foraging for natural foods at the bottom. 

Koi fish are considered to be a significant pest to freshwater ecosystems. It is basically because of their rather unusual way of hunting for food. They take in big gulps of food and separate the dirt and mud.

Types of Koi Fish

There are a variety of koi fish that you can see. These fish can reach a length of up to 3 feet, making themselves one of the largest cyprinids. Female koi are larger and have rounder bodies than male ones. Typically, their fins are rounded and short, with lobed caudal fins. However, many breed these varieties for their long trailing fins. 

Koi fish care

These gorgeous fish appear in various striking colors. They are typically silver or white, with bright scales and colorful spots and markings on them. These markings can be gold, red, orange, black, or deep blue. Depending on their markings and colors, there are Japanese koi fish (the most common), butterfly koi fish (have long pectoral and caudal fins), black and white koi fish (white with black markings and spots), and gold koi fish (Ogon fish).

Koi Fish Keeping Environment

Now, as you have got a basic overview of different koi fish and their behavior, it is time to know how to take care of your koi fish. 

1. Koi Fish Pond

If you intend to keep koi fish in your backyard pond, you must have a proper setup for that. They prefer living in ponds, lakes, and streams with muddy bottoms and minimal flow. You can find these fish in both tropical and temperate areas with water temperatures above 70°F. They remain most active during the dimly-hit hours at dusk and dawn but will swim and hunt during all hours of the day.

So, your job is to replicate these conditions in your pond, which is very simple. Koi fish can grow to be large. Considering their living environment, they can even live up to 25-30 years. Some exceptional koi even live up to 100 years. Therefore, having a proper koi fish pond condition is essential. 

Pond Koi Fish

The ideal pond size for keeping koi fish is at least 1,000-gallons of water. The essential point to remember when planning the size of your pond is the depth of water. You must keep it in at least 3-foot deep water to help your koi find warmer water when cold and cooler water in the summer. One thousand gallons of water should provide enough space for five koi fish if all water parameters are correct.

Also, make sure the bottom of your pond is not covered with hard pebbles or rocks.  Most koi fish lovers use a perfectly smooth base or fine gravel. It is practical as koi spend most of the time at the bottom of the pond. The pH of your pond should be maintained between 6-9. You can use crushed limestone in your water to maintain your pH. 

2. Feeding Koi Fish

People keep koi because of their beauty and stunning look. So, it would help if you took good care of them. Their color and overall health are very much impacted by the way you feed them. If you provide them accurately, you will attain excellent results. Thus, it is necessary to know the right amount and type of food you give to them. 

These fish are known for their enormous appetites and have a similar diet to goldfish. They are omnivores. This means that they eat seeds and plant material, algae, and insects. Although they do not prey on other fish, they may eat their eggs.

Feeding Koi Fish

In a well-set pond, they will find vegetation and critters to munch. An even mix of both commercial and natural foods is the best diet for them. If you give them any commercial food, make sure it has a high-protein level. You can also feed them bloodworms and river shrimps. 

However, you have to be very careful about not overfeeding them. There are many negative impacts of overfeeding koi. Give them enough food that they can gulp in five minutes. If you see anything left thereafter, make sure to correct the limit next time. Feeding of koi varies with temperature too. They eat more in a higher temperature and less in colder. 

3. Keeping Koi Safe

Keeping koi safe should be your other priority. After all, you would never want to find them dead. One of the fatal diseases is herpesvirus or KHV (Koi herpesvirus). This is a highly contagious virus that affects all varieties of the common carp. If one of your koi fish is infected with KHV, there is an 80% chance of it dying. 

These infections can be prevented by carefully examining the health of any new carp that you include in your pond. You should quarantine any fresh fish you bring for two weeks before placing them in the pond. 

Apart from this, you must know that koi are known as notorious jumpers. Sometimes, after jumping out of the water, they get back. But the other times, if they can’t do the same and are left unattained, they can die. 

Should I Quarantine My Koi Before Introducing It to the Pond?

One of the frequently asked questions is the necessity of quarantining koi before introducing it to a pond. So, is it vital to quarantine it? The answer is yes. It would help if you quarantined your koi before leaving it in the pond with other koi or fish. But why is it essential to quarantine a koi?

koi fish variety

Quarantining a koi is a critical job that one must do. Once you bring home a new koi fish, make sure you quarantine it for two weeks at least. It is because the newly purchased koi may transmit bacteria, parasites, fungi, or viruses. And even after maintaining all other precautions, all it takes is to overlook a parasite’s microscopic unhatched egg to infect everyone in the pond. 

Even if your koi is healthy and clean, shifting it overnight can make your fish exhausted. Thus, it can decrease their immunity, making them vulnerable to many diseases against which your other fish are already immune. Therefore, you must keep your new koi quarantined before leaving it in the pond. 


As much as keeping koi fish is an exciting job, it is also necessary to know koi fish care techniques. Learning about koi fish ponds and their types helps you understand their responses better. We have tried to cover all the necessary details in this guide. That said, we hope that this guide was helpful enough for you. Have a pleasant time with your fish, and may they live long! 

Leave a Comment