There are many factors to consider when designing, installing, and maintaining your koi pond, and your geographic region’s unique characteristics play a role in determining what is best. Koi are able to hibernate in cold climates and adjust to warm summers, but it is important to take appropriate measures to protect them from predators and the elements. Where you live determines how to best build and maintain your pond, choose plants and accessories, and care for and protect your pond population.


Koi can withstand the New England winters as long as the pond doesn’t freeze. Enthusiasts in this region should ensure their ponds are at least six feet deep, as the pond is less likely to freeze as it gets deeper. Another way to keep your pond from freezing is to purchase a pond heater or a de-icer.

A variety of predators in this region could pose a threat to your koi, including raccoons, mink, bullfrogs, snakes or snapping turtles, and fish-eating birds. Great blue herons, green herons, and belted kingfishers are ones to watch out for. Even screech-owls and red-shouldered and broad-winged hawks occasionally take smaller koi. In some parts of the northeast, bears also can be problematic, as they can prey on koi and damage your pond. Equipping your pond with the proper deterrents for these predators will help keep your koi safe. 

Precipitation is a factor you will need to consider in this region, as rain and snow can bring pollutants into the pond. In addition to your regular water tests, you should check the water after every heavy rain or snowstorm. Plants to consider for your pond include hornwort, elodea, American water lotus, water iris, and water smartweed.


Midwesterners share similar challenges with the northeast region when caring for koi ponds in the winter months. The safest pond depth for your koi will be about seven to eight feet in order to offer a protective pocket at the bottom where the water will be warmer. Additionally, you will need a pond cover to protect your pond from high winds and debris.

If your property is on or near farmland, it is important to keep chemicals from crops out of your pond. They can disrupt your pond’s ecosystem, and endanger the lives of your koi. Don’t build your pond close to areas where it may be susceptible to agricultural spraying, and design it to block runoff. Plants to consider for this region include water lilies, hornwort, elodea, pickerelweed, and American water lotus.

Pacific Northwest

Most ponds should get at least five to six hours of direct sunlight per day. This can be difficult during the rainy seasons in the pacific northwest, so avoid building your koi pond directly under trees, overhanging shrubs, or other heavily shaded areas.

Because this region is so prone to precipitation, diligent monitoring of your pond’s pH is important. Enthusiasts in this region should also test for kH, a particular measurement of water hardness. Pacific Northwest water is typically low in kH, which you will need to restore to keep your koi healthy.

Aquatic plants to consider for this region include Water Lettuce, Hornwort, Elodea, Pickerelweed, Mosquito Fern, Water Clover, Sacred Lotus.

Rocky Mountains

Maintaining adequate aeration is the biggest regional concern for mile-high koi enthusiasts. The higher the altitude, the more difficult it becomes for water to absorb and retain oxygen. Although adding plants or even a waterfall will increase oxygen flow in your pond, you will likely need to take additional steps.

A bottom drain is useful in koi ponds because it pulls the water with the lowest oxygen content to the surface where it can be replenished. Koi ponds that have only a skimmer and no bottom drains will typically have problems with aeration because the water at the bottom never circulates to the top. Air pumps and air stones can help in the summer months when oxygen levels in the water tend to be lower. You also can combine a bottom drain and an air stone. The aerated bottom drain creates a rising column of air. Fluid bed filtration technology is another way to aerate a koi pond. This involves sending air into a basin filled with bio media, providing an oxygen-rich environment.

Position your pond away from uphill slopes to avoid rainwater runoff, which can carry grass, soil, debris, and chemicals. If a slope is unavoidable, build a ridge and dig a small ditch around your pond to channel runoff.

In the Rockies, cranes, herons, raccoons, kingfishers, snakes, foxes, wolves, and bears all are local threats to your koi population. Plants to consider for your pond include hornwort, elodea, pickerelweed, water clover, and American water lotus.


If you live in this region, the freezing temperatures that plague other enthusiasts are not a concern. However, you will need to be equally as cautious about the summer months when you experience intense heat.

Your pond should be at least two feet deep and built in an area with shade. Between one-third and one-half of your pond should be filled with aquatic plants.

As warmer water is less able to hold onto oxygen, consider performing routine water changes using colder water. Circulation also helps keep a pond cool. Your biological and mechanical filters should be placed across the pond from each other to skim and circulate the water. Test your water temperature regularly, and add oxygen to the pond if it approaches 80 degrees.

While plants in cooler regions typically shed their leaves annually, some desert plants can shed their leaves up to 5 times a year. Check your pond for debris regularly. Water hyacinth, hornwort, pickerelweed, mosquito fern, water clover, sacred lotus, waterlilies, mosaic plant, and water lettuce are all good options to consider for your pond.


Southeasterners will face the same troubles as other areas of the country that experience intense heat. In addition, water in this region will evaporate quickly, and bacteria will grow faster. Heavy rainfall can disturb your pond water’s pH. You will need to monitor pH carefully during the rainy seasons, and adjust it as necessary.

Hobbyists in this region experience more algae bloom than other areas. You will need to clean your filters and water valves and perform water changes of at least 10 percent every week. If algae growth still is a problem, you can add netting or introduce a pond dye to the water. Additionally, you can reduce the protein in your koi’s diet. This will encourage the koi to eat the algae.

The most common predators to watch out for are raccoons, the great white egret, and the blue heron. Plants to consider include tropical water lilies, water hyacinth, water lettuce, hornwort, elodea, pickerelweed, and water clover.

Ready to choose a new addition for your pond? Visit our website to shop our full selection of koi and goldfish.

2 responses

  1. Gary Stevens :

    live in sc have been battling the alge been rainy here for the past few weeks waters green ,time to flush it out agian

  2. Find the Koi do find in the Northwest. We keep ultra violet light in filter system to keep algae down and the water safe from bacteria. This is our second Koi pond. We bought 5 inch Koi from Next Day Koi two years ago . The Koi are about a foot long now and the Gold fish are 6 inches long. Half the pond is open to sun most of the day when the sun shines, half is shaded by a shed. Koi love the Northwest.

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