How to Care for Koi in Spring: What You Need to Know

Spring is an exciting season for koi keepers. Ice melts from the pond’s surface, the water begins to warm, and your fish slowly show signs of life again. You may have been a little worried about your fish through the winter, and then breathed a sigh of relief to see them moving about. Still, with temperature fluctuations that are typical in spring, your koi need a little tender loving care this time of year.

A good way to help your koi start the season healthy, is to clean the pond and add beneficial bacteria. Koi are ectothermic, which means they have little ability to maintain a constant body temperature, which is usually a bit warmer than the water in which they live. Keep in mind, their immune system isn’t very operable in temperatures below 50 degrees Fahrenheit, so they need all the help they can get in springtime.

While your koi’s immune system is slowly becoming more effective as water temperatures warm, many species of bacteria and protozoa are quickly becoming very active and reproducing rapidly. This means your fish are at greater risk of becoming sick. Cleaning the pond in spring and adding beneficial bacteria helps reduce the likelihood of illness.


Two Koi in Pond

Feeding Koi in Spring

Koi will start looking for food when the water temperature warms up. Although it’s tempting to feed them, avoid doing so until the pond water consistently reaches 50 degrees Fahrenheit. And then, only feed them sparingly since their metabolism is governed by the surrounding water temperature. Overnight temperatures can chill the water to below 50 degrees and then the food will move very slowly through the fish’s digestive tract. Undigested food decomposes inside the gut and leads to internal bacterial problems. It’s much better to wait to feed your fish until the pond’s water temperature is consistently at 50 degrees or above.

In addition, you should avoid high protein fish food in the spring and instead choose a food that’s specially formulated for cooler temperatures, such as Aquascape Premium Cold Water Fish Food Pellets. A pond thermometer will help you know when it’s safe to start feeding them. When water temps stabilize above 60 degrees, you can switch to a higher protein food such as Premium Fish Food Pellets. Avoid using food left over from last year; you want to ensure your koi have a healthy diet of fresh food.


Colorful Koi Being Fed in Pond

Cleaning the Pond

Most pond owners clean their pond in the spring, whether they do it themselves or hire a Certified Aquascape Contractor to do it for them. A cleanout helps to remove any remaining debris that may have accumulated during fall and winter. Rocks are power washed, and filters are cleaned. Adding Pond Starter Bacteria after the cleanout will kickstart your pond for the season and ensure a healthier environment for your finned friends.


Changes in Behavior

It’s not uncommon to notice changes in the behavior of your fish during the spring season while plants are still growing, and temperatures fluctuate.  Our fish symptoms chart will help you identify possible problems while providing options for proper treatment. You can also employ easy-to-use water test kits to help you identify any water issues.

Enjoy your fish, avoid the urge to feed them too soon, and take notice of changes in behavior or appearance. Remember, koi can live for many years and will provide great enjoyment if you provide a proper home for them.