Best Filters for Smaller Aquariums (3 to 5 Gallon)

best filters for small aquarium
Care & Maintenance

The best small filter for fish tank housing Betta fish or other small tropical fish like Neon Tetra or Guppies should be chosen carefully. In addition to purifying the water, a proper filtration system will function without agitating the water and stressing out your fish.

The following article will include information on a few suitable small aquarium filters as well as copious information on how each one works to accomplish its task. Be sure to consider the individual needs of your small fish when selecting the ideal nano tank filter for your tank.

Best Small Fish Tank Filters Reviews

1. AZOO Mignon Nano Aquariums (Max – 3.5 gallons)

Best for: Tanks as big as 3.5 gallons with Smaller Fish Species
Type: external power filter (Hang On Back)
Filtration: biological or mechanical


A filtrations system that is too strong can be trouble, Shrimp, Guppies, Neons and Betta can be sucked into the filtration chamber and killed. Furthermore, if the water is consistently being agitated by a forceful filter, the fish will consistently “swimming upstream” and this is no way to live. But if you need a slow and easy filtration system perfectly suited to the needs of small fish and tanks, this nano fish tank filter protects your fish with an adjustable flow rate system.

Quiet, compact and very easy to clean and maintain, the AZOO Mignon Filter 60 is the best small aquarium filter for tanks 3.5 gallons and smaller. In addition to adjusting the flow rate, a small pre-filter sponge prevents fish from entering the filtration chamber. The filtration chamber is also considerably large and does an impressive job purifying your fish tanks. You can also choose filter media you know is best for your fish types.

2. Deep Blue Professional (Max – 4 gallons)

Best for: Nano Aquariums holding 4 Gallons
Type: external power filter (Hang On Back)
Filtration: biological or mechanical


This Nano tank filter features a flow control interface that allows the owner to create a ideal habitat for Smaller Fish and other bathing beauties that like clean and un-agitated water. The Deep Blue Professional Nano Filter has a large filtration chamber that can be fitted with the filtration media of your choosing. There is also a filtration cartridge that can be used and replaced as needed and this makes the whole process a bit easier. The biological filtration of this product can be enhanced with Bio-sponges making an especially pure water supply for small fish.

3. Zoo Med Nano 10 External Canister Filter (Max- 5 gallon)

Best for: Aquariums up to 5 gallons with Smaller Fish Species
Type: Canister Filter
Filtration: mechanical, biological and chemical
Good For: Salt and Freshwater Tanks
Kit Includes: Bio-ceramics, Carbon Media, Sponges and Spray Bar System

A canister filter like this may cost a bit more than your average power filter, but you can bet the service level will be geared to the special needs of your fish tank. This option also comes with all the details needed for a complete setup including spray bar and several options of filter media.

This canister also performs all the filtration types you will need mechanical, biological and chemical for keeping fresh water tanks and salt water properly cleaned. You can also use the filtration media that best befits your tank in the extra-large filtration chamber, even if it is not the type you found in the package.

4. Sponge Filter (Max-5 Gallons)

Best for: Aquariums up to 5 gallons with Fry or Breeding Fish (more than one Filter can be used for Larger Tanks e.g. 2 for a 10 Gallon Tank)
Type: Sponge Filter
Filtration: mechanical, biological

The sponge filter offers some important benefits for a fish tank that will be dedicated to breeding or small fry fish. This option is powered by a standard fish tank air pump that traps the debris and contaminants in the water. Because the suction power is distributed evenly across the sponge there is no point of strong suction. This means that even the smallest fry is safe to feed and grow without being taken for a ride through the filtration system.

This is options is also very easy to clean and maintain. Just rinse it out in water until you notice all the debris and contamination in the sponge is gone.

Note: It is important to clean out the sponge with water from the aquarium as water from the tap can be contaminated with chlorine which will kill the helpful bacteria in the sponge and can even harm the fish when returned to the tank.

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