I don't know where you are, other than the USA, but there's a group called NANFA that specializes in native fish. There are a number of really interesting and appealing `southeastern native fish in the US - some killies and livebearers other than Gambusia affinis. Some of the absolute most interesting aquarium fish is are in the pygmy sunfish group, Elassoma. I've kept two species and while they are challenging, they are extremely interesting. They are really beautiful when they colour up.
They aren't tropical community fish because of water temperatures.
They aren't tropical community fish because of water temperatures.