The best shape for a koi pond is one that promotes good water circulation, allows easy cleaning, and provides enough space for the fish to swim comfortably. Generally, simple shapes like ovals, circles, or rectangles work well because they avoid sharp corners where debris and waste can collect. Smooth, rounded contours help water move efficiently, making it easier for the filtration system to do its job.
Deep areas with sloped sides encourage waste to settle toward the bottom drain, which helps maintain cleaner water. While decorative shapes may look appealing, overly complex designs can create stagnant zones and make maintenance more difficult. It's also important to ensure that the pond has a consistent depth of at least three feet in most areas, giving koi plenty of vertical space to move and hide from predators or temperature extremes.
