A Hobbyist’s Guide To Taking Care Of Koi Fish

A pond is a lovely addition to your outdoor space. For one, it’s an eye-catching element that serves as a decorative focal point or as a space to unwind. The best way to bring life to your pond is to add Koi fish, which come in various vibrant colors that you’ll surely love.

Koi fish are the ornamental variants of the common carp (Cyprinus carpio), belonging to the family Cyprinidae, which includes all minnows and carps. The increasing popularity of aquariums and ponds in homes made Koi fish and other similar breeds famous.

Koi fish caring and breeding date back to the 19th century in Japan–where farmers have native carps in the rice gardens. Ever since, caring for a Koi fish has been a custom in Japanese culture, especially since it’s often associated with bringing good fortune in life.

If you’re eager to add a pond with Koi fish to boost the beauty of your outdoor space and make it more inviting, there are several considerations to think about. Here’s a guide on how to take proper care of Koi fish.


If you’re wondering how much are Koi Fish, the standard varieties of Koi fish you can find in most backyard ponds are available from USD$50 to USD$80. There are also special varieties you can buy from a breeder or specialty shops.

Since imported Koi can be very costly, the fish are cared for in pristine conditions. Most medium and high-grade Koi can fetch a high price tag–ranging from $200 up to $1000 or higher.

Pond Size

Koi fish requires at least 250 gallons of water. If you plan on creating a large school, it’ll need up to 1000 gallons.

The depth of the pond should be a minimum of 6 feet and include both shallow and deep sections. A rule to remember is to keep 10 gallons of water for every inch of fully grown Koi fish.


In their natural habitat, the common carp can only thrive for up to 20 years. As for those kept in captivity, Koi fish can live up to 50 years under proper care.

On average, the Koi fish life expectancy can range from 25-35 years in captivity with optimal care. Hence, the better you care for your fish, the longer their lifespan will be.

taking care of koi fish

Filtration System

Fish produces waste that turns into ammonia, nitrites, and nitrates. It can reach a point of toxicity that can be harmful or even kill your Koi fish in high amounts. A filtration system is also crucial for your pond as it ensures a healthy and comfortable environment for your Koi fish by dealing with the wastes.

You can choose from these two chief types of filtration systems:

• Biological: This filtration process involves culturing aerobic bacteria that break down the wastes.
• Mechanical: This process handles physical debris such as dead leaves, fecal matter, etc.

When choosing a suitable filtration system for your pond, it should filter most of the pond water every hour. Depending on the volume of your pond, the filtration system should have the appropriate pump capacity and speed.

Pond Setup

Ideally, the pond should be in concrete with a rubber lining and a muddy substrate at the bottom.

If you want to provide the ideal environment for your Koi fish, it’s crucial to maintain temperatures between 74-86 degrees F throughout the year. For you to regularly check the temperature, invest in a pond thermometer. This is especially helpful in areas with cold winters since a heating system can prevent the water from freezing. As for blistering conditions, a portable shade can help maintain the temperature of the pond water.

The pH level of the pond must range between 6-9. Remember, the addition of crushed limestone to the water can help maintain the pH levels. You can also consider adding water hyacinth, pickerels, water lilies, cattails, floating pondweed, and duckweed, all of which are types of plants that’s best for your pond.


In their natural habitat, these fish have large appetites and have a diet similar to goldfish. As omnivores, they feed on seeds, algae, plant material, zooplankton, and insects. Koi won’t prey on other fish but may eat their eggs.

In your pond setting, make sure that you’ll provide a mix of both natural and commercial foods. A Koi will readily eat aquatic plants and algae. With this in mind, offer a good stock of algae and floating weeds. Also, you can satisfy their love of zooplankton by introducing brine shrimp and water fleas to the pond. Additionally, you can provide insects and larvae that you can find in aquarium stores.

As for commercial food, you should provide a high protein option. Koi fish will feed at all levels of the pond. This means you can offer pellets that can reach all depths.

Most of the nutrition of these fish will come from whatever they find in your pond. Thus, it’s best to provide three small portions of pellet food per day. For convenience, an automatic fish feeder set for two times a day works best.


Caring for Koi fish in an outdoor pond can be a rewarding activity. A Koi pond serves as an aesthetic element to your property while also functions as a space for everyone to relax while observing the vibrant fishes swim through the pond. Although Koi fish requires proper care and maintenance, this helpful guide will help keep your Koi fish happy and healthy for years to come.

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