Population control is typically easy with the majority of domesticated pets. It is usually as simple as removing the possibility of conception until the time in which the opportunity has passed. Unfortunately, this is not the case with Koi. Koi, no matter whether you want them to or not, will spawn and lay eggs, and other Koi will fertilize them. It is nature, and there is little you can do. Since contraceptive methods are not available for fish, population control really comes down to removing the unwanted babies after they are already born.
As a newcomer to this hobby, you may simply disregard this information. For whatever reason, whether it is that you feel removing unwanted babies is cruel, or if you believe that the more fish the merrier, you will quickly realize that keeping all the babies that are born could be a potentially harmful situation to both your pond, and the original parent fish.
Why Are The Babies Harmful?
What is so harmful about having more fish the your originally started with? Well a number of harmful situations can happen.
First, Koi can and will grow up to three feet in length. Koi, unlike some other fish, will grow, no matter the size of their habitat. This will turn a beautiful pond in a wasteful, extremely overpopulated pond. Not only will to many fish cause damage to a smaller pond, but they will not be comfortable in their habitat.
When you originally set up your pond, surely you set the filtration system up for a specific amount of fish. Adding extra fish without adding more to your system will ultimately cause a surge in unwanted gases and chemicals in the water that is dangerous to your Koi.
Getting Rid Of The Babies
There are several ways of removing babies from your pond.
One way is to stop feeding your Koi the minute you realize that spawning has occurred. You should stop feeding your Koi for no less than three weeks. Do not worry about your Koi starving, as they will focus more on natural foods if you are not feeding them daily. This “natural” diet includes their young. Koi are not cannibalistic animals by any means, but they will eat their young when they are still eggs or if they are small and resemble insects. Once the baby Koi actually resemble real fish, and the adult fish recognize this, they will no longer see them as food, so it is important to start this process as soon as you notice spawning or babies.
While this is a process of nature, you may still find this method to be cruel or unusual. Another way of removing unwanted babies from your pond is to give them away.
First, check with your local pet store. Many pet stores have programs in which they will accept unwanted animals and give them good homes. Some may even pay a certain amount for each fish, since they sell them, but do not count on this. Local zoos may also have programs.
If you know of a local Koi society, you may let them know that you have unwanted babies. Alternatively, you can find a message board or group online and post messages there. Who knows, you may even start another person on a Koi keeping hobby.