How to Raise Healthy Kois

Kois make fascinating pets. If you are a newbie, raising Kois might seem to be a little daunting however you will soon realize that caring for these brilliantly-colored fish is definitely rewarding.

Here are some important tips to help jump-start your knowledge on koi care and other general koi knowledge:

  • Koi are quite hardy and are relatively easy to raise. They may be highly resistant to disease however their health is heavily dependent on two important factors— water quality and their diet.
  • Your koi will thrive well in ponds filled with lots of water. Seasonal ponds should be at least half meter deep while year-long ponds should be at least 1.5 meters (4.5 feet) deep. A koi pond should be filled with at least 1000 gallons of water, coupled with gravel substrate, rocks, and aquatic plants. Since Koi are quite tolerant to cold weather, they can withstand existing pond conditions even in winter.
  • Water temperature in the pond should be kept between 60-75 degrees F (about 15-25 degrees C).
  • Make sure at least 50% of your pond has some form of shade, since your koi need to spend time under the sun and shade.
  • Even though your pond is outdoors, you still need to install a pump to circulate and promote aeration. Koi thrives well in an oxygen-rich environment. You can also choose to install a waterfall or fountain to enhance water oxygenation.
  • Vegetation in the pond is very important. Apart from being a viable source of oxygen, plants, such as water lilies, provide safe places to hide against predators. Koi will also feed on some species of aquatic plants such as water lettuce.
  • During winter, your koi’s metabolism will slow down and your fish won’t eat during the coldest months of the year. However, they will continue to produce waste in the form of nitrogen, thus it is important to have an avenue where this toxic gas can be released. Some hobbyists use a trough heater that keeps a small opening at the surface of the pond throughout the winter, providing an outlet for the gas to escape and keeping your fish safe from dangerous accumulation of nitrogen in the water. You can also install a bubbler to help circulate the pond water and prevent freezing. However, a de-icer will be needed to maintain an open outlet in colder regions.
  • If you need to bring your koi inside during the winter, make sure that your koi tank has plenty of room. As a rule of thumb, allocate ten gallons of water for every inch of fish. Oxygen and food should be given throughout the course of the winter season. When spring comes, you can put them back into the pond when the water temperature reaches 50F. Make sure to gradually expose your koi to the water temperature to give their bodies time to adjust to the difference in temperature.
  • During summer, koi are very active and their appetites can increase the amount of nitrogen and other metabolic wastes in the water. Testing the water for ammonia or nitrite should be undertaken regularly and be sure to take action by increasing oxygen levels and doing a partial water change to prevent the occurrence of health problems and other risks.

About the Author:

Peter Hartono is the founder and CEO of Just Aquatic - a proud Australian company that offers top of the line aquarium supplies and gold fish tank supplies carrying top of the line brands including API, biOrb and Exo Terra.