Cloudy water in a koi pond can result from several common causes, often related to the pond’s ecosystem balance. One frequent reason is suspended particles like dirt, debris, or algae floating in the water, which can happen after heavy rain, wind, or pond cleaning. Another cause is a bacterial bloom, where beneficial bacteria multiply quickly to break down organic waste, temporarily making the water appear milky or cloudy.
Overfeeding koi can also lead to excess uneaten food and fish waste, overwhelming the filtration system and causing water to become murky. Poor or insufficient filtration is another factor, as filters help remove particles and maintain water clarity. Testing the water for ammonia, nitrites, and nitrates can reveal if pollution or imbalance is contributing to cloudiness. Improving filtration, avoiding overfeeding, performing regular partial water changes, and maintaining a good balance of plants and bacteria can help clear cloudy water.
