Why do koi fish only swim on the bottom of the pond?

Koi fish may primarily swim near the bottom of a pond for several reasons, including their natural behavior and environmental factors. The bottom provides shelter from predators and a stable environment with more consistent temperatures and oxygen levels. Additionally, koi often forage for food and explore the substrate, leading them to spend more time in this area. However, they will also swim near the surface, especially when feeding or interacting with other koi.