A Beginner’s Guide to Keeping Koi Carp

Koi are a variety of the common carp (Cyprinus carpio) and are a popular fish to keep in ornamental ponds due to their bright colours and patterns. Koi carp were first bred in Japan in the 1700s by rice farmers and were seen as a symbol of luck, good fortune, and prosperity.  These fish live an average of 50 years, with the oldest known one being 226 years old! 

If you are looking for a beautiful, adaptable fish to put in your garden pond, Koi carp could be the fish for you! Here is a beginner’s guide to keeping koi carp.

Types of Koi 

There are over one hundred varieties of koi carp. As there are so many – and more being developed daily, breeders categorise the fish according to their scale type and colour combinations. One of the first varieties, and most popular to this day, is Kohaku. This type was established in 1890 and is a white fish with orange-red markings. There are a total of 13 classifications of koi, including Sanke, Showa, Bekko, and Hikarimuji. Koi are available in colours such as black, white, gold, red, silver, and orange. If you visit your local aquatics store, such as Complete Koi and Aquatics, you will be able to see a range of fish and decide which colours are most appealing to you.

Feeding

Koi are omnivorous, meaning that they eat animals and plants. If you decide to keep these fish, you can feed them certain plants, snails, and worms. Generally, they are bottom feeders and sift through the muddy substrates on the bottom of a pond for food, but commercial fish food is available that has a mixture of morsels. Some components of the food sink and some float so that you can encourage the koi to come to the surface of the water to enable you to monitor their physical health. During the winter months, or when the temperature dips below 10 degrees Celsius, koi will go into a hibernation-like state and should not be fed during this time.

Habitat

Koi can grow up to 120cm in length but usually average around 60cm. Their size is dependent on the quality and temperature of the water they live in, genetics, the capacity of their home, and the type of food they consume. 

These hardy fish adapt well to different temperatures, but their immune systems can be compromised when the water temperature drops below 10 degrees Celsius. In order to thrive, they need their habitat to be 15-25 degrees. The pH of the water is important to monitor too. Although koi can tolerate a pH range from 6.5 to 9.0, they cannot handle a rapid change, so stability is the key.

The size of the pond affects the growth of the fish as they will release hormones that will inhibit their growth if they are put in an environment that is small or overcrowded. It is recommended to house one koi per 1000 litres of water.