6 Best Filters For 55 Gallon Tanks Reviewed For 2024

Filters play a vital roll in your tank’s health.

In this article, I’ll show you how to choose a filter for a 55 gallon fish tank, and review the 6 best options available and reveal the number one pick.

Quick Overview: Top Pick

For HOB filter, the best for a 55 gallon tank is the Seachem Tidal 55

For canister filters, the Fluval 407 is what you should look at

And if you want some quiet and low maintenance, the Marineland internal filter is your go to.

Why do you need a filter for your aquarium?

There’s sometimes confusion among new aquarists about exactly what an aquarium filter does.

Many think that a filter just keeps the water moving so it doesn’t get stagnant.

That’s technically true, but the main purpose of an aquarium filter is a bit more complicated than that.

The Nitrogen Cycle

It’s kind of gross, but true, fish and other livestock in your aquarium constantly put off wastes (urine and feces) into the water.

This waste sinks to the bottom of the tank and starts to rot. As the waste breaks down, it puts off deadly ammonia (NH₃). 

Left to itself, an aquarium with fish in it will become unlivable as fish waste builds up and puts out more ammonia. The ammonia will increase until the water is so toxic that all the fish die.

Luckily, there is a natural process, known as the nitrogen cycle, that breaks down the ammonia in aquarium water.

Living in your filters are colonies made up of millions of beneficial bacteria (also known as nitrifying bacteria) that detoxify ammonia, making your aquarium water safe.

Pro Tip: It takes time to get your filter to build up the beneficial bacteria you need to process wastes and make your tank safe for fish. For a more in depth discussion of the nitrogen cycle, please check out this article.

Biomedia 

There isn’t enough surface area inside a filter box to house all of the beneficial bacteria you need for your fish tank.

So aquarists add special materials, known as biomedia, to their aquariums so that there is plenty of room for bacteria to grow on. 

Biomedia is usually made from some sort of porous material, like unglazed ceramic or sintered glass, that has tons of little nooks and crannies that are perfect homes for beneficial bacteria, kind of like apartment buildings for microscopic critters.

It takes millions of nitrifying bacteria to process even a small amount of fish waste so it’s important to have as much biomedia as possible in your filter. That ensures you have plenty of room for all of the beneficial bacteria your tank needs.

Pro Tip: For more information about different kinds of filter media, please check out this article.

Why I’m Not a Big Fan of Filter Cartridges

A lot of filter companies will try to sell you on the idea that filter cartridges are great, that they make filter maintenance easier and give you everything you need to keep your tank healthy.

I think they’re a huge waste and here’s why.

A filter cartridge is just a plastic frame that holds some activated carbon, sandwiched between some pieces of non-woven plastic pad. 

That’s it, there’s no magical elves in there that scrub your tank clean.

The carbon is only good for a few weeks, then you have to throw the whole thing out and add a new cartridge. And those things are NOT cheap. 

There’s a huge debate about whether or not you even need the carbon in the first place! 

Some say that carbon is the best thing since sliced bread, others think it’s a big waste since it doesn’t remove ammonia, nitrite or nitrates.

I’m on the side that it’s a waste. I have run many successful tanks without any carbon in the filter for years!!

I only add it when I need to filter out meds after having to treat a tank for some kind of illness. As I’m sitting here, I literally can’t even remember the last time I even bought carbon.

Plus, when you throw away the cartridge, you’re also throwing away any beneficial bacteria that have grown on the surface.

So you’re throwing away the bacteria you do need so you can replace the carbon you don’t AND it costs a small fortune.

Nope, no thank you, not gonna do it.

I am a much bigger fan of using some sort of reusable sponge or other material for mechanical filtration and then using all the other available space for biomedia. 

GPH

GPH stands for gallons per hour. It’s a measure of how much water the filter pump can move in an hour.

It’s recommended that you get a filter with a GPH that is at least four times your tank volume. For example, for a 55 gallon tank, you want a GPH of at least 220.

But, more is always better. Don’t be afraid to have a GPH that’s eight or ten times your tank volume.

6 Best 55 Gallon Filters Reviewed

Seachem Tidal 55 (Top Pick For HOB)

Key Features:

• 250 GPH
• Internal motor
• Self-priming 
• Surface skimmer
• Adjustable intake flow
• Heater holder
• Filter media basket
• Bottom up flow design

The Seachem Tidal really is one of the best hang-on-the-back filters available. 

It has a 250 GPH internal motor, meaning that the motor stays inside the aquarium. The main benefit of this is that you never have to prime the filter (fill the back of the filter with water).

This is a huge benefit because you don’t have to worry about this filter starting up on its own after a power outage. Since the motor is already in the water, it will just start suctioning as soon as the motor kicks on.

It also features a heater holder that will let you snap your heater right onto the side of the filter. This puts the heater in the highest flow area of the tank, allowing for even distribution of heat throughout the tank.

You can also adjust the flow on the output, lessening the current in the tank.

The thing I like the most about this filter is that it doesn’t use cartridges. Instead, it has a large media basket that you can pack with whatever kind of media you like. 

The basket already has a reusable sponge for mechanical filtration so you can stuff the rest of the space with biomedia or even a net bag with carbon if you wanted.

The Tidal also features a bottom up flow design. So water is pushed through the bottom of the media basket and forced to flow through the media above before it can escape out of the front. 

This is important because other designs can fail to push water through media, letting it just flow around it, making it less effective.

I don’t really think the surface skimmer is necessary, it’s more of a gimmick. Also, it can suck in things you don’t want, like food you just added.

Also, there’s no way to cover the surface skimmer to keep fry or shrimp from getting sucked in and killed. So this filter is definitely not a good choice for fry or shrimp tanks.

Pros: 

• Self-priming
• Large biomedia capacity

Cons: 

• Surface skimmer makes it unsafe for shrimp and fry

AquaClear 70

Key Features:

• 300 GPH
• External motor
• Adjustable flow
• Large biomedia capacity

I have to admit my bias towards this filter, I have this exact one on my 55 gallon cichlid tank.

There are some things that I love about this filter, and then other things I’m not crazy about.

First of all, it’s got great flow. I’ve always been impressed about how well this keeps all the water in the tank moving.

If you want a little less, you can easily adjust the flow down, it takes only seconds.

And it has a huge biomedia capacity, which I love. 

It also comes with a large reusable sponge that is great for mechanical filtration.

You can easily add on a sponge pre-filter if you plan to keep shrimp or fry in the tank.

My one gripe with it is the external motor. This filter has to be primed or it will not start. And sometimes, like after a short power failure, it won’t start on its own even if the back is full of water.

So far (knock on wood) I’ve always been able to get it to start back up by taking off the motor and manually turning the impeller a few times, but it can be pretty annoying.

Pros: 

• Large biomedia capacity
• Reusable sponge
• Can be made shrimp/fry safe

Cons:

• External motor can be touchy starting up after power loss

Fluval C4

Key Features:

• 264 GPH
• External motor
• 5 stages of filtration

The Fluval C4 is a fairly sophisticated filter that forces water through several chambers containing different media.

It has several stages of mechanical media, an area for activated carbon and a chamber that holds ceramic biomedia.

My only gripe with this filter is that they didn’t dedicate much room to biological filtration. But, you could put extra biomedia in the compartment meant for carbon.

This does have an external motor that you will need to prime.

Pros: 

• Multi-stage filtration

Cons:

• Small biomedia capacity
• Not self-priming

SunSun Hw303B Canister Filter

Key Features:

• 370 GPH
• Canister style filter
• Large media baskets
• UV sterilizer

This canister style filter really is the next level of filtration. It has huge baskets that can handle up to a pound of ceramic biomedia each. It also comes with reusable pads for coarse, medium and fine mechanical filtration. 

You can run carbon if you want or dedicate more room to biomedia.

It also includes a built in UV sterilizer that is meant to kill bacteria, viruses and algae spores in the water column.

One gripe is that canister filters can leak if their main gasket isn’t seated properly or wears out (this is true of all canisters, not just this one). Make sure to carefully follow the manufacturer’s instructions for installation and maintenance to avoid leaks.

Also, maintenance on a canister filter is much more of a job than a hang-on-the-back. But, if you’ve got a heavily stocked tank, nothing can beat the biomedia capacity of a canister.

Pros: 

• Huge biomedia capacity
• Multilevel mechanical filtration
• Built in UV sterilizer

Cons:

• All canisters can develop leaks if the gasket wears out

Fluval 407 Canister Filter (Top Pick Canister Filter)

Key Features:

• 383 GPH
• Vertical mechanical media
• Three tier media chamber

The Fluval 407 is honestly the coolest canister filter I’ve ever seen. 

It features a big insert that holds coarse and medium mechanical media, but instead of it laying in a horizontal tray, it’s in a vertical position. This ensures that all water moving through the filter has to go through the reusable sponges.

It then has three trays for other media: fine mechanical, biomedia and carbon. Once again, I’d skip the carbon and load that tray with more biomedia. 

The only thing that I can gripe about is that at $199.99, this filter is pretty pricey. But, it has awesome features and I’m a big believer in the reliability of Fluval products.

It also draws very little power, only about as much as it takes to run a household LED bulb.

Pros: 

• Huge biomedia capacity
• Energy efficient

Cons:

• Expensive 

Marineland Magnum Internal Canister Filter (Top Pick Low Maintenance)

Key Features:

• 290 GPH
• Internal filter that operates inside the aquarium
• Large filter media compartment

This marineland filter is a bit different than all rest since it is an internal filter, which means the entire thing sits inside the aquarium itself.

Inside the body of the filter are layers of mechanical filtration that can be cleaned and reused. At the very center is a chamber where you can place biomedia and/or loose activated carbon.

Since the motor will always be underwater, there’s no need to prime it. This filter is also very quiet because the water will muffle any noise.

The only real downside is that it is a little bit of an eyesore in the tank. But, you can easily hide it behind plants and decor so it’s not very noticeable.

Pros: 

• Very quiet
• Self-priming 

Cons:

• Can be an eyesore since the canister is inside the aquarium

Which One is Best?

If it were up to me, I’d choose either the Seachem Tidal or the AquaClear for a hang-on-the-back filter.

Both have great biomedia capacities and reliable motors. But the AquaClear would be the frontrunner for a fry or shrimp tank.

Between the canister filters, I would definitely go with the Fluval 407. I really like the design and I have a lot of faith in Fluval products. I’ve always found them to be high quality and very reliable.

I think the Marineland internal filter would be great for anyone looking for low maintenance and quiet operation.