|The regen area is typically filled with plants like lilies and cattails. (fncponds.com)|
While you won’t be able to have a whole school of goldfish or tons of massive koi in the water, between 5 and 10 fish are acceptable depending on the size of the pool. These fish should not be fed as this will add more waste to the system. Goldfish are very adept at finding their own food in a system like this. If you add fish make sure you only add one gender as they are notorious for reproducing. The aim of these systems is to create a balance. With goldfish constantly reproducing, you’ll have a hard time doing that.
Every natural swimming pool is different. They come in many designs from a traditional pool with the natural regeneration area to something that could easily be mistaken for a koi pond if it wasn’t for the diving board. I know that if I ever have the funds, I’ll be looking to install one of these beauties in my backyard.
|Typical swimming pool with a regen area on the left. (Enricoslasheric @ Wikipedia)|
Natural pools are functional in the summer but are still an attractive landscape feature in the off season.
|Very natural-looking pool with regen area in upper right (ecolagoons.com)|
I can post pictures here all day long. I love looking at these things because every single one is different. They also give me ideas for how I would design a natural pond.