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There are many products claiming to be the best small aquarium filters on the market today. But before discussing some of them, it’s best to know the science behind good water quality that will allow an aquatic ecosystem to thrive. From the biggest to the smallest aquarium filter, you need the appropriate mechanism to achieve balance in the biotic and abiotic environment of your aquarium because that’s the only way for your fish to grow healthy.

Why Does Such a Small Tank Need an Aquarium Filter?

When it comes to small fish tanks, maintaining water quality can be problematic due to the lack of water volume. Adding a fish tank not only helps clean your tank but also adds water volume to your tank. It may not be a lot but a little goes a long way. Some filters, however, do not offer extra water volume – internal filters and sponge filters. HOB filters and canister filters do! There’s a lot that is expected of the standard tiny aquarium filter. The main purpose of this device is to clean the tank and make sure that beneficial bacteria are present for a healthy ecosystem. The device will do this in three ways: mechanical, chemical, and biological filtration.

In mechanical filtration, any particulates are removed by filtering foreign objects through a small media. This can be in the form of pads, foams, filter flosses, or paper pleats. They can come with the product when you buy it, or you can scour pet shops for these items. In chemical filtration, any toxins like ammonia or nitrites are removed from the water. The best small fish tank filter can easily sift even the excess nutrients that can, later on, affect water quality in your aquarium. With the filter, you don’t have to change the water often, which is not really advisable considering that you are throwing away beneficial bacteria in the process.

In biological filtration, you need to understand what a nitrogen cycle is. A nitrogen cycle involves the waste products of all the living things in your fish tank being converted by fungi and bacteria into ammonia. With the small device, the harm brought about by this toxin is minimized. You must also keep in mind that the more fish you put in the tank, the faster the nitrogen cycle accelerates. You need a filtration device to cope with the quick changes. The best small aquarium filter should be able to provide mechanical, chemical, and biological filtration for your tank.


Top 5 Best Filters for Small Aquariums

These products are not in order, they are all great products

1. AquaClear 30 Power Filter

This one is a workhorse as it churns about seven times the capacity of other products on the market in terms of aquarium volume of filter filtration. You can also customize the performance and efficiency of this filter through its control feature. Installing it is quite easy, and maintenance is pretty straightforward. As the name suggests, the max capacity of this product is around the 30-gallon level. This is the best filter for a small aquarium because it makes sure that beneficial bacteria are preserved, which will greatly help in removing nitrates and ammonia from the aquarium. Here you can find the AquaClear 30 Power Filter!

2. Zoo Med Nano 10 External Canister Filter

Take note that this small fish filter only has a capacity of 10 gallons. The bioceramic, carbon, and filter sponge are extremely versatile as they can clean freshwater or seawater. It’s very easy to install and maintain. This filter is also very silent, and the return flow is just right for small fish. This is the best filter for a 10-gallon tank. Here you can find the Zoo Med Nano 10 External Canister Filter!

3. Aqueon Quietflow Internal Power Filter

This small tank filter has the option to adjust the return flow rate as well as the height and direction of the water return. However, this one works only for a 10-gallon aquarium. It’s smaller than what one would expect, but don’t let the size fool you. This filter performs way beyond expectations. The head can be moved so you can angle the water stream. This product is included in the best small aquarium filters list for a reason, and that’s because the Aqueon Quietflow works as advertised. The motor is very quiet, unlike some products which produce noise like a diesel engine. Here you can find the Aqueon Quietflow Internal Power Filter!

4. Aqueon QuietFlow LED PRO Aquarium Power Filters

The activated carbon in this filter will make sure that your tank is free from discoloration, toxic chemicals, and stinky smells that can harm your fish. Credit goes to its bio-holster, which the company patented and can remove nitrites and ammonia. If that isn’t enough, there’s an additional fail-safe feature which is the diffuser grid that can clean out the remaining toxins. The filtration process itself has four stages: mechanical, chemical, and biological, to wet/dry stages. This is to ensure that your fish are swimming in the safest and cleanest water. Some customers suggest that you buy your own media instead of using the ones that come with the box for optimum filtration. Here you can find the Aqueon QuietFlow LED PRO Aquarium Power Filters!

5. Lee’s 13210 10 Original Under Gravel Filter, 10″ x 20″ (Needs an Air Pump)

This is another one of the best filters for small fish tanks. The body is made of hardened plastic which resists breakage and cracking. Safe for small fish or shrimp as there is no intake to suck them in. Water is gently drawn through the substrate (it acts as a mechanical and biological filter). In order to move the water, you can use either powerheads or air pumps. For smaller fish tanks I always recommend using an air pump as it provides a gentle flow. One of the common complaints is how the installation is made slightly complicated. Luckily with the power of the internet, I provided a video below about how under-gravel filters are set up and how they work. Here you can find Lee’s 13210 10 Original Under Gravel Filter!

How do Under-Gravel Filters Work?

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Out of the top 5 products above, which product is most cost-effective and gives you the most bang for your buck?

The Verdict?

Out of the shortlist of small aquarium filters, the AquaClear filter is the superior choice by far. You can control the water flow without sacrificing the efficiency of the filtration. This is perfect for small fish or delicate plants. Once you cut down the flow rate, the water in the filter chamber will be processed several times. The cartridge filtration system also ensures that beneficial bacteria remain in the tank instead of being sucked into the device and thrown out when you dump the cartridge. That means the beneficial bacteria in your aquarium will have to re-colonize again, so make sure that you have a high-quality small aquarium filter.

Use a Pre-filter!

Watch out for your small fish or shrimp! To be on the safe side you should buy pre-filters if you are going to keep small fish or freshwater shrimp. Typically, these are sponges that prevent your fish from getting sucked into the motor. A pre-filters only purpose is to protect small creatures, they also keep debris from getting in. There are many products on the market, and sometimes, it can be intimidating to find the best small aquarium filters on your own. But you can start by assessing the high-quality products outlined above. Remember that all brands have various pros and cons. In the end, the final decision will be up to you when it comes to choosing an aquarium filter that suits your needs.

If you like the article above, here are some other similar articles you should check out!

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Hi, my name is Jordan. I've been in the fishkeeping hobby since my childhood. Welcome to my blog where I help fishkeepers enjoy the hobby by offering free guides, advice, & product reviews. Read more...

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