u/The_Silesia_one

I recently made the discovery that my stream, connected to my garden, now had a small family of fish in it. It's odd because the stream is usually very shallow and very small, so the only "real" native species that houses here are crawfish. Idk if these are kois or something else. Can someone help me? If those are kois then I know these are not natural cause in the rivers where I live, kois are not natural.

The stream is a part of the bigger river 'Wupper' in western Germany, in the "Bergisches Land"

To know exactly what this type of fish is in my creek/stream, I caught one of them and put them, temporary, in a container full of water before releasing them into the stream again.

https://docs.google.com/document/d/1GF5j7cl5RkxttClmlri5MXRk3YcmNMXDolErvLKbQjo/edit?usp=drivesdk

Here are some pictures I took of the fish. It kinda looks like a Koi, but I'm scared to catch them both and put them into the artificial pond of my neighbour because I don't want them to get eaten

edit: What can I do? Can someone tell me what exactly type of fish this is?

edit 2: I included a few pictures of the pond my neighbour has