This is an overview of a 2nd year pond I installed for a Garden Center. Lots going on, I think it looks pretty good. The waterfall and stream enter in from the left. The pond is about 30x16 in dimension.
Koi, the key is great filtration, and to not have overload-in other words too many fish to overload the system. This is a delicate balancing situation. Unfortunately most folks think the more fish the better. I would actually like to see homeowners add more Shibukunki, Fantails, and Comets instead of the more demanding Koi. Especially those who aren't that enthusiastic about being hands-on with their waterfeature.
Easily my favorite Aquatic plant, the Lotus but it must be held in check or it will easily get out of control-easily. Not only is the flower spectacular but the foliage is great also. On top of that after the flower leaves the seed head left behind is an intriguing focal point.