I hope I don't get downvoted, yelled at, and burned at the stake for asking this, but I don't know where else to pose the question.
I've got a decent-sized koi pond, about 6,000 gallons. I have both koi and comet goldfish in it, and my problem is that the goldfish are breeding out of control. I am thinking about adding a couple small predatory fish (likely green sunfish from the neighboring lake) to eat the excess comet goldfish while they are babies. I am wondering if anyone has ever done anything similar, and if so, what experiences they had with it.
To provide more detail, the pond is going on 4 years old. When I got it, I bought several 2 to 3 inch baby koi and put them in. They promptly vanished. I talked to a friend with a pond, and he said predators (probably raccoons or wading birds) had clearly eaten my koi. He told me that sadly, I probably just had too much wildlife around, and I wasn't going to be able to keep koi. He said I should just get some comet goldfish instead.
I took his advice, and I bought a dozen feeder comet goldfish from the pet store and put them in. Then, two weeks later, my koi reappeared! It turns out they were just shy about being introduced into the pond, and they were hiding in the rocks. Once they acclimated to their new homes, they came out, and they've been fat, happy, and growing ever since.
The snag is, the dozen comet goldfish are fat and happy too, and they spawn like crazy. The original dozen has expanded to about seventy, and they just went through another round of spawning this spring. I have a shallow "bog" area with plants on one side of the pond, and there are easily about a hundred new babies this year, each about the size of a grain of rice. Even if only a percentage survive, it's too many goldfish!
Nobody wants comet goldfish, and giving them to someone who might put them in a fishbowl doesn't seem ideal anyway. I thought maybe a couple small predators like green sunfish would be big enough to eat most of the new babies, but small enough to not bother my koi.
What do you think, Reddit? Am I crazy? Or might it work?