Would you consider pond fish pets?

Goldfish that live happily in an outdoor pond grow to a much larger size than if they are confined to a small fish tank, and carp can live a long time when they are well looked after in a nice outdoor environment.

If you have a pond you can put both species together, and you can get them in a variety of patterns and colorings. The important thing when keeping fish outdoors is to protect them from preditors. Make sure local cats cannot catch them, and provide sheltered areas with plants or netting to protect them from a passing heron or other large bird that could swoop down and take them.