(04-01-2013, 05:17 PM)Rube Wrote: 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.
Actually that is not true. Fish size has nothing to do with the size of the fish tank whatsoever. Yes, I have heard of this false rumor from the novice fish keepers. It is false. It is the very reason why we recommend people to get fish tank big enough for the adult full size fish rather than their current size. If the fish tank is too small, the fish will outgrow it. No, you will not see the fish become too big to move. What will happen before that is the fish produce way too much ammonia for the undersized tank to take, and it will end up dead.
If one day I have a pond of my own, I will have koi fish in it.
As for predators, it is rare to have cats fishing from the pond. This practice is fairly common with raccoon. I doubt they can catch a large koi fish, but smaller goldfish is fair game for them.