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    We purchase every product we review with our own funds — we never accept anything from product manufacturers.

    Shopping Guide for Best Aquarium Filters

    Keeping fish can be a fun, relaxing hobby – and they’re definitely low-maintenance pets. A fish isn’t going to wake you up at two in the morning to go for a walk, after all.

    But that doesn’t mean that maintaining healthy fish is easy. For fish to thrive, they must have the proper environment, and that takes a lot more than simply pouring some water into a tank and letting the little guys swim away.

    To ensure that the water is as clean and healthy as possible for your fish, proper filtration is key. That’s why choosing the right aquarium filter is so important.

    Unfortunately, choosing an aquarium filter isn’t as easy as you might think. There are so many different types on the market that finding the right one for your tank can be tricky, especially if you’re new to maintaining an aquarium.

    At BestReviews, our goal is to help take some of the confusion out of the shopping process. We never accept products from manufacturers, so our reviews are completely unbiased. We conducted field and expert research to examine the top aquarium filters on the market. Our hard work allows us to pass along all the info you need to make an educated shopping decision for your aquarium.

    Ready to buy an aquarium filter? Take a look at the matrix above for our top recommendations. For general information on aquarium filters, continue reading this shopping guide.

    As your fish grow in size or you add more fish to your aquarium, you may need to increase the size and power of your filter to make up for the growing amount of waste.

    What Does an Aquarium Filter Do?

    An aquarium filter helps remove fish waste, excess food, decaying organic materials, toxic chemicals, and other debris from the water in a fish tank. Removing these materials is crucial to the health of your fish, because they can build up to dangerous levels and poison the fish if they’re left to accumulate.

    Your aquarium’s water can also become cloudy if you don’t have an effective filter, making it difficult for you to enjoy your fish.


    Your aquarium’s water can become cloudy if you don’t have an effective filter, which makes it difficult to enjoy your fish.

    Types of Aquarium Filtration

    Three broad types of aquarium filtration exist: mechanical, chemical, and biological.

    • Mechanical aquarium filtration drives the aquarium’s water through some type of filter material that catches particles or debris.

    • Chemical aquarium filtration usually focuses on specific chemicals or nutrients that are found in excessive amounts in the aquarium’s water. The chemicals pass through some type of filter media or resin which removes them from the water.

    • Biological aquarium filtration involves allowing certain bacteria to grow in the aquarium. The bacteria help remove the ammonia created by food, waste, and fungi, which can be toxic to fish. For biological filtration to be successful, you must have enough space in your aquarium for the beneficial bacteria to grow.

    After you purchase a new filter, rinse all of its washable parts in clean water before placing it inside your aquarium.

    Staff  | BestReviews

    Types of Aquarium Filters

    Not to be confused with types of aquarium filtration, there are several physical prototypes of aquariums to choose from. It’s important to select the right one for your aquarium. Here’s an in-depth look at your choices.


    Sponge/Air-Driven Filters

    Sponge filters, also known as air-driven filters, use an air pump to push and pull water through a sponge that provides both biological and mechanical filtration. This type of filter works best for smaller aquariums.


    Undergravel Filters

    Undergravel aquarium filters sit beneath a layer of gravel in your aquarium and pull water through the gravel to provide biological filtration. They usually require replacement cartridges, but undergravel filters are relatively inexpensive compared to other options. This type of filter works best for small or large aquariums, though the fish load should be light.  


    A sponge filter can be an excellent supplement to another filter or used on its own in a smaller aquarium.

    Staff  | BestReviews

    Power Filters

    Power filters are the most common type of aquarium filter and can provide biological, chemical, and mechanical filtration. They typically hang on the back of the tank and require replacement cartridges. This type of filter works well for most aquarium sizes.


    Internal Power Filters

    Internal power filters are submerged completely in the aquarium’s water, so they can save a great deal of space. They offer extremely effective filtration and can move the water well because they’re usually placed at the bottom of the tank. This type of filter works best for small aquariums that are 20 gallons or less in size.

    Many aquarium experts recommend having two filters per tank, just in case one should fail.


    Canister Filters

    Canister filters offer excellent mechanical, biological, and chemical filtration for large aquariums or those with a large fish load. They can hold several different types of filter media inside the canister for the best water quality possible.


    Wet/Dry Filters

    Wet/dry filters provide extremely effective biological filtration. The biologic media is exposed to both water and air, which allows a large number of beneficial bacteria to grow. This type of filter works best for a large aquarium.


    Fluidized Bed Filters

    Fluidized bed filters hang on the back of the aquarium and pump water through sand or silica chips. Bacteria grows on the filter media to provide very effective biological filtration. This type of filter works best for smaller aquariums.

    Choosing the Right Aquarium Filter Flow Rate

    An aquarium filter’s “flow rate” refers to the number of gallons of water the filter can pass through it each hour.

    For effective filtration, an aquarium filter should be able to pass four times the full volume of the tank through it each hour. For example, if you have a 20-gallon tank, you need a filter with a flow rate of at least 80 gallons per hour.

    If your ideal flow rate falls between two filter choices, always opt for the filter with the higher flow rate.


    Keep your fish limited to just one per gallon of water; your filter cannot handle an overstocked fish tank.

    Aquarium Filter Prices

    Aquarium filters vary in price based on their size and type, but you can expect to pay between $10 and $200 for one.

    • $10 to $40: You can get a small, basic aquarium filter in this price range.

    • $50 to $80: In this price range, you can get a fairly powerful filter of medium size.

    • $90 to $200: You will find some large, powerful aquarium filters in this price range.


    • As your fish grow in size (or you add more fish to your aquarium), you may need to increase the size and power of your filter. The reason: the more fish you have, the more waste there will be, and the greater your need for filtration.

    • Read the manufacturer's instruction manual to learn about proper maintenance procedures. In general, it’s a good idea to clean your aquarium filter at least once a month.

    • Use lukewarm water to clean your aquarium filter parts.

    • Overfeeding your fish can make it more difficult for the filter to adequately clean the water. Be sure to feed your finned friends the recommended amount of food.

    • To verify that your aquarium filter is working properly, use a water-testing kit to check ammonia and nitrate levels. They should both be at or close to zero. If they’re higher, your fitler isn’t getting the job done.


    Depending on the type of filter you have, you’ll likely need to change the filter cartridge or media once a month.

    Staff  | BestReviews


    Q. Does using an aquarium filter mean I don’t have to change the water in my fish tank?
    While a filter helps keep the water clean, you still need to perform regularly scheduled partial-water changes to maintain water quality. In most cases, that means replacing about 25% of the water with fresh water to dilute any problematic elements.

    When you’re choosing a spot for your aquarium, avoid locations that are near windows, direct sunlight, air vents, or heavy traffic.

    Q. What maintenance does an aquarium filter require?
    Depending on the type of filter you have, you’ll likely need to change the filter cartridge or media once a month. At the same time, you should remove the filter from the tank and clean all of the components according to the manufacturer’s instructions. The proper way to clean a filter depends on its type, so be sure to consult your owner’s manual.

    Q. What type of filters work best for large or extra-large aquariums?
    For larger aquariums, canister filters are a good choice because they are large and powerful enough to handle a greater number of fish. Wet/dry filters also work well for large tanks of up to 120 gallons.

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