The process of being caught and netted causes significant stress for koi, triggering a stress response that can severely impact their growth and even lead to illness. Therefore, it is crucial to minimize such handling unless absolutely necessary. The key is to develop the ability to diagnose common issues without having to physically remove the fish from the water. Of course, there are situations where capture is unavoidable, such as for administering specific treatments, conducting detailed health assessments, or during selective breeding activities. In these cases, always handle the fish with extreme care using soft, water-filled nets or bags to minimize stress, and keep the time out of water as brief as possible.
