Hey everyone, this is a purely hypothetical question, for a very hopeful but far future regarding the growth of goldfish and or koi in ponds.
I would love someday down the road to set up a nice large pond, either a concrete above the ground pond in my basement, or a dug out and properly lined and done pond in the yard.
Either way it would be at least a few hundred gallons, and at least a foot or so deep, providing what would appear to be plenty of space for swimming happiness and growth.
My question mainly comes from seeing massive goldfish and koi at such high prices for ponds, it seems that they all come from the same small fish, but a 12-20" koi or goldfish can cost several hundred dollars, and some even top 1000. So really I just don't know if it's extremely hard to raise the small goldfish/koi to these sizes, or if it's just a matter of people wanting to fill their pond with massive fish right from the get go.
I would love to stock my pond with goldfish still under 10 inches, and be able to raise them to large adult size just by giving them what they need to do so, but I just don't know if it's so much harder than it sounds from seeing these ludicrous prices.
And kind of away from the original question, would it be crazy to have an indoor pond with a sand substrate and plants? It sounds to me like it would be a really pleasant way to set things up, but it seems that most indoor ponds are just a pool of water with stones and a fountain. Doesn't seem to give the fish much of a life, but I don't know if there's a reason they do it this way.