Cycling a new koi pond means establishing beneficial bacteria that help break down harmful waste products like ammonia and nitrites, creating a safe environment for your fish. When you set up a new pond, it doesn’t have this natural bacterial colony yet, so it’s important to start the cycle before adding koi. You can begin by introducing a source of ammonia, which can come from fish food or pure ammonia, to feed the bacteria. Using a biological filter with good filter media provides a surface for bacteria to grow.
Testing the water regularly helps track ammonia, nitrite, and nitrate levels. At first, ammonia will rise, then beneficial bacteria will convert it into nitrites, which should later drop as another type of bacteria turns nitrites into nitrates, a less harmful substance. This process can take several weeks, and patience is key to avoiding stress or harm to fish. To speed up cycling, some people add filter media or gravel from an established pond, which contains helpful bacteria.
