We have both. A water garden pond that has its own niche and a Koi pond for the Fish. They peacefully co-exist... as two separate and distinct features designed for two distinct and separate purposes. My wife dearly loves her water garden and I enjoy it. I love our Koi pond and she enjoys it. The Water Garden benefits from the Koi pond water changes (providing nutrients to the plants) and the Koi pond benefits from the decorative value of the water garden with none of the problems associated with mingling the two in the same body of water.