Last year we dug a pond on the alotment. The plan is to let it become a haven for frogs, toads and newts as they will eat lots of bugs and pests that would otherwise munch their way through my crops. We also want the pond to be a water source for the bees (I've seen plenty of them gathering water from the edge of the pond recently). Within weeks of filling the pond last year, we saw frogs in it.
A couple of weeks ago I caught some movement in the pond in the corner of my eye. It looked like a fish. I assumed what I had seen was a newt. I now think I was wrong. Today I saw a fish in the pond - I had a good view of it, not just a glimpse. Quite how it got there is difficult to say. We certainly didn't put it in. There is no stream feeding the pond that could bring fish to it. No one else has access to it. What we think has happened is that there may have been some fish eggs on some pond plants we added last year. Last summer a friend gave us some pond weed from his garden pond which is brimming with goldfish.
Now that we have fish in it, we may look at adding fish we can eat. As yet, we know very little about keeping fish for food so we will have to look into this further. We may also need to create a second pond. I suspect fish will eat frog spawn so a smaller, separate pond for the amphibians would be useful.