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Best Koi Pond Filter

Best Koi Pond Filter

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Well-loved for their beautiful colors and adaptability, koi fish are also said to be bringers of good luck. However, koi care and maintenance isn’t as straightforward as you might think. These fish can get messy, especially when feeding and expelling wastes, so it’s important to install a koi pond filter and ensure that the fishes’ home is kept sanitary. Now, you might wonder, What are the best koi pond filters?

The best koi pond filter systems include Aqua Ultraviolet Ultima II 1000 Filter, OASE BioSmart 5000 Pond Filter, XtremepowerUS Koi Pond Pressure Bio Filter, and Aquascape 95053 UltraKlean. These are based on different factors, including size, price, overall performance, and warranty. In the following article, we’ll talk about how you can choose the best koi pond filter and the features of the top koi pond filter systems to help you pick the filter that satisfies your needs.

Role of Filters in Koi Ponds

A pond filter maintains the sanitation of the fish pond through two filtration stages — biological and mechanical. Biological filtration often includes two phases. The first phase makes use of a special substrate that promotes the growth of friendly microorganisms. These tiny fellows make nitrates out of koi waste, which benefits not only the fish but also the plant life in the pond ecosystem.

The second phase involves the use of ultraviolet light, which eliminates unfriendly microorganisms, preventing infestations and koi sickness. Meanwhile, mechanical filtration involves physical filters that seep out unwanted elements out of the pond. To ensure a thorough sweep of the koi pond, a multi-layered filtration system is recommended.

Choosing the Best Koi Pond Filter

Acquiring the best koi pond filter is vital in maintaining the pond’s cleanliness and the optimum health of koi fish and getting the most bang for your buck. Below, we’ve listed the different areas to consider to help you pick what’s best for your needs.

Pond Size and Fish Population

First, make sure that the filter is big enough for your koi pond and can accommodate not only the current number of your koi fish but also the projected population in the future. Otherwise, it might not be able to handle their waste, especially as koi fish eat more and grow in number.

Filter Type

One important decision to make is choosing between a pressurized and a non-pressurized pond filter. The former generally has a slower water flow than the latter. Pressurized koi filters provide a more thorough filtration and cover a larger area. However, they’re on the pricier end. Meanwhile, a non-pressurized filter offers better biological filtration. While it’s more affordable, it offers inferior installation flexibility.

Warranty and Price

There are plenty of koi pond filters that aren’t crazy expensive, and if you have the funds to buy koi fish and build a koi pond, you’ll most likely have the funds to buy a quality filter. If you’re on a budget, however, choose a pond filter that has at least adequate and reliable filtration specifications. A substandard filter can cost you more money or even your koi fish in the long run.

Also, pass on any koi filter that offers a warranty period of less than a year. Since koi filters, like any mechanical device, are susceptible to damage or malfunction, it’s better to get a device with a long warranty period.

What Is the Best Koi Pond Filter System?

What Is the Best Koi Pond Filter System

  1. Aqua Ultraviolet Ultima II 1000 Filter

Aqua Ultraviolet Ultima II is perhaps the best small koi pond filter you can find, which can accommodate koi housing up to 2000 gallons. Its small form factor means that it can easily be hidden from view, allowing for a more natural and unobstructed koi pond view.

It offers superb biological and mechanical filtrations. The filter also has a backwashing feature. Through just a weekly valve rotation, you can easily expel unwanted materials and maintain a clean pond for your koi fish. The one thing that seems to go against this filter, apart from its volume limitation, is the price. If it’s within your budget, this would indeed be a worthy choice.

  1. OASE BioSmart 5000 Pond Filter

If you want a quality koi pond filter that won’t break the bank, check out the OASE BioSmart 5000 Pond Filter. It can do the job for a pond or aquarium up to 1250 gallons in volume while keeping things uncumbersome with its built-in cleaning system.

As an added convenience, it comes with several indicators for temperature, cleaning, and waste drain, making monitoring and upkeep easier. The drawback to this model, however, is its less sturdy build, requiring careful use to ensure longevity.

  1. XtremepowerUS Koi Pond Fish Pressure Bio Filter

If you’re wondering what’s the best large koi pond filter, XtremepowerUS Koi Pond Pressure Fish Pressure Bio Filter is the answer. At a relatively affordable price, you’ll have a capable koi filter that can handle a pond of up to 4000 gallons in volume. It comes with great features, such as a backwashing mechanism, multi-layered pressurized filter, and cleaning indicators.

However, this filter doesn’t have the best durability. Nevertheless, if you’re careful with it, it’s still a pretty solid option.

  1. Aquascape 95053 UltraKlean

The Aquascape 95052 UltraKlean is not only a great product out of the box, but it also offers one of the longest warranty periods for a koi filter. You can get warranty services and benefits for three years, so you won’t have to worry about any repair or spare-part expense for some time.

It’s well-built, even coming with multiple filtration systems for maximum effectiveness and light indicators for ease of use. The slight downside to this model is that it’s not advisable for places with particularly cold weather, thus giving it limited geographic usability.


Picking the best koi pond fish filter will not only keep your fish healthy but also maintain the cleanliness and aesthetic of your pond. Some of the best koi pond filters are Aqua Ultraviolet Ultima II 1000 Filter, OASE BioSmart 5000 Pond Filter, XtremepowerUS Koi Pond Pressure Bio Filter, and Aquascape 95053 UltraKlean.

By considering several factors, including the size, filter type, price, and warranty, you’ll surely get the koi pond filter that works best for you and your koi fish.

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