Strangest thing, I recently added a small preformed section onto the side of my pond with a little stream between the two and shortly afterward moved a few hornwort plants and a lily to the new section...about a week later I noticed lots of small things swimming around that didn't look like tadpoles...woohoo...they were little fish! My only problem is now I have no idea how to tell whether they are goldfish or koi because I have both in my pond. Any suggestions anyone?