Answer
Can you have fish in a natural swimming pond?
Possible but not usually recommended; fish add nutrients that upset the balance.
In short
It is possible but not usually recommended. Fish add nutrients that can upset the balance a natural swimming pond relies on to stay clear, and they are better suited to a dedicated wildlife or koi pond. We talk through what you want from the water before designing.
Arrange a consultation
Send a few photographs and a sentence about the site. We will reply personally.