A Koi pond can be a charming and attractive addition to your home, either as an outdoor yard feature or decorative indoor water garden. These “living jewels” and “swimming flowers” are known for a gracefulness in the water that most find people find relaxing and meditative.
How small can a koi pond be? Not very small. At least 1,000 gallons, and no less than three feet deep. A watery home for Koi needs to be large enough to accommodate some rather large fish. Adult koi can grow quite large and need ample space to swim.
While 1,000 gallons might sound like an overly big pond, keep in mind that while a few, six-inch koi may find that size pretty spacious, within four years, each of those fish can quadruple in size. Before long, among the adult koi, swimming space will be very tight.
Why Do Koi Need So Much Space?
While the average healthy goldfish can grow to four inches long, that’s just about where a koi begins. And once a pond is built, it’s an incredible undertaking to make it bigger down the road. So, it’s best just to start as large as you can go.
Here are some reasons why these colorful and portly beauties have such a need for depth and volume of water.
|Koi get big||A fish that is even a foot-long needs quite a bit of space to spin around and change direction, let alone swim enough to get proper exercise.|
|They can live for a very long time.||The average lifespan of a koi is 20-30 years. They’ll be around for a while. And they keep on growing.
|Colder zones need a deeper pond. ||In winter, a Koi pond needs more depth to keep from freezing solid, if the fish are to survive.
|They don’t react well to rapid temperature change.||The smaller the volume of water, the greater the speed at which it heats up or cools down. If a pond is too small, extreme heat and cold can quickly affect the koi.|
|There are predators in your yard.||A shallow pond makes it too easy for ducks, hawks, raccoons and other wildlife to reach the fish.
|Big fish generate big waste.||Koi ponds require very regular cleaning as it is. A pond that is too small will be a real struggle to keep clean. Koi waste can add up fast.
Determining What Size Pond to Build
If you’re considering a koi pond, start by thinking about how many fish you’d like to keep in it. And then double that. Keep in mind that you might end up with more fish than you start with. They’re really pretty and you might want more down the road!
Just how big is a pond that holds 1,000 gallons? At the minimum suggested depth of three-feet, a 1,000- gallon pond would be approximately 6 feet wide by 8 feet long. And that size pond will comfortably house just five, average-size koi. More fish, bigger pond. So, if you approximate five fish to every 1,000 gallons, you can estimate what size pond you will need, depending on the number of koi you want to keep.
Don’t want a rectangular Koi pond? If your pond holds enough water, you can make it any shape you like. To determine how many gallons you’ll need – or the volume of your pond – multiply the Length x Width x Depth of your shape. Clearly, this won’t work as easily for ovals or odd shapes.
This is when an online pond size calculator, like this one, comes in handy to do the math for you.
Maintaining an Outdoor Koi Pond
Once you have that much water – and several new koi – to take care of, it’s important to know how to keep the underwater environment and the fish healthy. As you might imagine, this involves some regular, daily maintenance year-round – and the proper equipment to make it go smoothly. While the following isn’t an exhaustive list, it will give you an idea of what is involved in the daily maintenance of your Koi pond.
|What You Need to Do||Supplies That Help
|Keep your water clean||Pump and filtration system
A long-handled net, skimmer
Plants around your pond
|Proper temperature, between 59-77° Fahrenheit ||Temperature gauge
Aerator or fountain
Plants around your pond
|Healthy oxygen levels||Aerator or fountain
Plants around your pond
|Keep water from freezing in winter||Heater
|Keep Predators away||A fence or pond-netting
A “predator statue”
What About an Indoor Koi Pond?
An indoor koi pond can be a gorgeous focal point in your home. And, in colder climates, it may be a great way to ensure healthy koi all year long with less worry and expense.
But an indoor pond still needs to be as big as you can possibly fit in your home.
Most likely, your indoor pond (unless it is in a commercial space with ample square footage), will be smaller than the recommended size mentioned above. Not many homes could accommodate a 1,000-gallon pond. Because of the smaller size of indoor koi ponds, maintaining excellent water quality and avoiding overcrowding are critically important measures.
Even indoors, your koi will still need room to swim and grow, so staying away from overcrowding is as important as ever. According to Pond Trade Magazine, the very minimum allowance is 10 gallons of water per one inch of fish. Or one, five-inch koi per 50 gallons of water. By this calculation, if you have a 300-gallon pond in your home, you can accommodate six, five-inch fish.
Keep in mind, those baby Koi will grow much larger! So, you are better off thinking in terms of 10-inch fish. In this case of the 300-gallon indoor pond, you would bring in three koi. Otherwise, to avoid overcrowding, you may have to give up adult fish as they outgrow the space.
Keeping a Healthy Indoor Environment
With less water volume, keeping healthy water levels in an indoor pond is crucial. Just like an outdoor koi pond, you’ll have to take steps to promote and maintain water quality, oxygen level and water temperature. In addition, because the pond is in your home, you’ll want to take additional precautions to help prevent damage caused by leaks or humidity.
Some of the things you’ll need for an indoor koi pond:
A high-quality water pump that can filter the entire pond in a few hours
An air pump to maintain a proper oxygen level in the water
Aquarium heater to help regulate temperature, when needed
A drain, if possible
A fan to disperse heat and moisture
Good natural light or incandescent lighting, especially if you have pond plants, too.
A water detector or leak alarm, just in case
Is it Expensive to Purchase and Keep Koi?
Koi fish can be very expensive. From pet shops to breeders, the price of Koi can range from $10 to upwards of $1,000, depending on what type of koi, how large they are and even how old they are.
Koi have many classifications, usually recognizable by colors, patterns and body shape. Some Koi are very carefully bred for certain characteristics and qualities, from specific color patterns to a particular gracefulness in the water.
According to the Business Insider, the most expensive Koi sold for $1.8 million in 2017. But some more common types of Koi are even available inexpensively online. Depending on the size of your pond and the type of koi you pick, stocking it can be a pricy endeavor. But, when maintained correctly, your new pond is sure to bring you years of fulfillment and relaxation for years to come!
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