Answer: Yes, koi are fine in the area. We have several ponds that have them in it, they do really well. And I mean, you can stock tons of them; it’s not really going to affect the pond as far as those fish by themselves. Now, as far as if you have other fish in your pond, they can affect the koi population. But you can stock them hundreds per acre if you want to without hurting the pond. But they can be eaten by other fish.