It seldom works out very well. To be any good, an environment has to be managed. It's about like turning some cows loose on the land. Somehow, a bull is going to get in. And before long, the cows will have pretty much overeaten the forage and face starvation or will break the fence and leave. Ponds aren't a lot different than that.
When the fish reproduce they have to have a predator and the predator will also reproduce. Sooner or later, it will become over stocked, and quite probably, an oxygen crash will occur.
Your question isn't all that unusual. Lots of people want maintenance free ponds. They just don't seem to work out as expected.
That said, I would try green sunfish or hybrid bluegills.
