Choosing The Right Goldfish Filter

There’s no doubt about it:

The type of goldfish filter you choose can make or break your success with fishkeeping.

It’s the main thing that stabilizes your entire aquarium environment, keeping your goldfish safe.

And let’s face it:

A decent filter is better than nothing and will save you some work, but a great filter will drastically reduce the number of water changes you need to do AND can maximize your stocking capacity.

Who doesn’t want that?

That’s why I’ve put together a list of the 5 best filters, in a variety of sizes, shapes and budgets, researching the benefits of each style and testing different brands.

Let’s dive in!

5 Amazingly Effective Goldfish Filter Options Compared


Why We Love it:

  • Extremely efficient ammonia and nitrite reduction for a hang on back filter

  • Current reduction options for fancy and slower-swimming goldfish

  • Wet/dry trickle chamber maximizes oxygen exchange and can allow for nitrate removal



Affordable, convenient, inconspicuous – the hang on back filter excels at all three.

The hang on back filter (sometimes abbreviated to HOB filter for short) is the most common filter you’ll find in pet stores and online. A small pump pushes water into a compartment stuffed with filtration media, and then back out into the aquarium.

Sometimes referred to as the all-in-one filter, as it can accommodate mechanical, chemical and biological filtration.  They are affordable and easy to conceal behind the aquarium.

The biggest problem has been that because they are so small, most HOB filters available on the market rely on a high water turnover to run efficiently (causing strong current in the water which can be stressful, especially to fancy goldfish breeds).

But good news:

The Fluval C model takes delicate fish species into account by adding a special wet/dry trickle chamber that can hold nitrate reducing filter media (which also provides a greater surface area for beneficial bacteria).

The trickle chamber allows the media to be exposed to oxygen and water at the same time so it can work much better than submerged media.  And the design of the filter allows you to turn down the flow without compromising the efficiency.

It is unlike any models available on the market and the only one I recommend for fancy goldfish keepers or any delicate fish.

If it were me, I would PACK every square inch of this filter with FilterPlus or Seachem Matrix, which can assist in nitrate removal and provide more surface area than any other media I know of.

Another tip:

Using the Fluval prefilter sponge on the intake of the filter is a really good idea, as it can reduce the time between filter cleanings and prevent nasty mulm buildup in the media which can make  your fish sick.

Why We Love it:

  • Powerful yet inconspicuous filter option

  • Flexible filter media options with lots of room

  • Perfect for heavily stocked aquariums


The canister filter provides a powerful filtration option. These filters operate by running water from the aquarium down to the filter underneath and then back up into the aquarium.

They can hold a LOT of filter media and don’t take up room inside the tank, giving your fish ample swimming room.  And if you don’t want a filter that’s intrusive, a canister could be a great option for you.

They are great for spaces where you want something quiet, such as in an office.

This one by Penn Plax gives you everything a canister filter should, while remaining affordable.  A big plus is the flow rate shutoff valves so cleaning is easier (a big complaint for most canister filters).

With canister filters, you’ll probably want to make sure you use a spray bar to distribute the current.

I pack my canister filters with jumbo ceramic balls.

They don’t trap debris.

They support nitrate reduction (seriously, my nitrates are almost undetectable every week when I test).

And the surface area for bacteria to grow is MASSIVE.

To prevent waste from building up at the bottom below the media (requiring more frequent cleaning) I make sure to put a sponge prefilter on the intake.


Now I only clean the filter every 6 months or so, and just wring the sponge out weekly or every other week.

Why We Love it:

  • Unmatched aerobic filtration for maximum ammonia, nitrate and nitrate removal

  • More efficient oxygen exchange than any other filter – without a strong current

  • External filter with massive filter media storage


Now, we’ll examine the wet-dry filter, also known as a “trickle filter” or sump.

They offer very powerful biological filtration, so powerful that it can even increase stocking density capabilities in your tank!  They are used by goldfish keepers who want to support a healthy load of goldfish without having to buy lots of smaller filters to do the job.

Returning water is super rich in oxygen, and if you use nitrate reducing filter media, you can really reduce your need to do water changes.

As in, some people only need to do monthly… or even every 3 months water changes.

When that nitrate drops to 0 on its own, your chains fall off! 😉

There are two main kinds of wet/dry filters: above the tank and under the tank.  For above the tank setups, water is pumped from the tank into a tray situated above the tank and trickles over the different layers of filtration media.  Like canister filters, what is inside is totally up to the aquarium owner. There are DIY versions, though these never seem to look very nice.

But this brand has a clean design and is very customizable.

Read More: Benefits of a Wet Dry Filter System


Why We Love it:

  • Provides more surface area for good bacteria to grow than any other kind of filter

  • Does not stress fish with too much current

  • Very affordable option



Don’t let anyone tell you Undergravel filters are outdated.

When set up correctly, these things can be AMAZING at filtering your goldfish aquarium.


You have a surface area for your beneficial bacteria that is literally as huge as the bottom of your tank, something no other filter can match.  That means a safer environment for your goldfish.

Traditionally, the UG filter is positioned under a layer of gravel at the tank bottom and pulls debris through the gravel bed.  However, goldfish shouldn’t be kept with gravel (it’s a choking hazard), and with this setup you can get a lot of poop trapped at the bottom, which can be hard to clean and bad for your tank’s environment.

But there’s a workaround:

Instead of pea-sized gravel, you can use hydroton, nitrate reducing filter media like Pond Matrix (comes in a 1 gallon size) or small pebbles (bigger than the fish’s mouth, though does not support nitrate reduction).

And instead of pushing waste down into the filter bed where it gets trapped and yucky, you can force it up the opposite way with a pump and use a prefilter on that pump to trap the debris, making cleaning so much easier.

Marineland’s powerhead offers the ability to easily reverse the flow for your Undergravel filter.  You can also attach their prefilter to it to prevent waste from entering your filter bed.

Simply connect the pump outlet tube to your riser tube with a reverse flow and enjoy a safer and more effective aquarium filter.

And guess what?

You can also use SAND with UG filters!

Read Full Article: How to Set Up an Undergravel Filter for Your Aquarium

Why We Love it:

  • Durable sponge does not disintegrate over time when squeezed

  • Provides aeration to the water

  • Gentle current perfect for delicate or baby fish

With superior surface area for bacteria to grow, sponge filters work by pulling water through the sponge with the help of an air pump attached to airline tubing and making a home for beneficial bacteria in the little sponge holes.

They are great for tanks with fry or small baby fish, as they won’t suck up young ones and provide a gentle current.

It’s a simple and affordable option, though it does require frequent cleaning to work well and does not support nitrate reduction.

I like to use them alongside a more powerful filter for a biological boost and increased aeration in the water.

This one is good for tanks up to 75 gallons in size.

Do Goldfish Need a Filter?

Short answer…


Long answer…

The truth is, goldfish need to have a filter, and you need to have one for your own sake as well.

Goldfish produce toxins (through their waste and respiration) that accumulate in the aquarium and can cause all kinds of major problems.

The purpose of a filter is to supply a multi-pronged approach to get rid of the nasty toxins and keep your goldfish safe using a combination of mechanical, biological and sometimes chemical filtration.

Theoretically, goldfish could live without a filter on one condition:

Huge daily water changes.

Those would effectively remove the toxins and keep the water safe for our finned friends.

But it isn’t practical for most people to be doing this for their aquariums! We have things to do besides carrying buckets all the time and paying a massive water bill. ?

Filtration stands in the gap between a dirty tank and going crazy with water changes.

It’s the missing link!

Read More: Do Goldfish Need a Filter?

What kind of Filtration is Best for Goldfish?

“Think of your goldfish filter as a mini sewage treatment plant.” – Goldfish keeper

There are 3 things to consider when it comes to picking out the best filter specifically for your goldfish.

1. Current

Common filter options like hang on back filters and canister filters hold less media.

That’s why everyone is always hyping having a high volume of water flowing through them, because without it there isn’t enough oxygen to keep the bacteria alive.

But guess what?

While athletic breeds like Common and Comet goldfish don’t mind current, fancy goldfish don’t like a strong current in the water.

Their fins are longer and catch the water current, blowing them around the tank or causing them to struggle to stay in place.

Sometimes they give up the fight and hang in a corner or sit at the bottom. This STRESSES the fish which weakens their immune system.

And what does a low immune system lead to…?


Not good!

2. Safety

Many filters are designed in such a way that they require frequent cleaning to stay clear of debris.

If debris is allowed to build up in a filter, in certain conditions it can become incredibly toxic.

Mulm (white gunky gross buildup) and sludge (brown gunky gross buildup) stress the immune system as they become loaded with bad bacteria, leading to sick fish.

3. Effective


Filtration is more than just trapping particles of fish poop or having clear water (though those are nice of course).

Filtration is about completely eliminating ammonia (the #1 killer of aquarium fish in the world) and nitrite, turning it into the much safer nitrATE.

To get rid of ammonia you need beneficial bacteria that consume it and turn it into a far less harmful substance.  A good filter has got to have lots of room for beneficial bacteria to grow – or it they can’t do their job.

Let’s face it:

The majority of filters on the market today are way too small to be effective for our “messy goldies.”

They just lead to a false sense of security for the hobbyist.

So choose one of the high performing brands above for best results.

Filtration Conclusions

What kind of filtration you choose depends on your lifestyle, the kind of fish you own, and the needs of your aquarium as a whole.

There is definitely a trade-off with the more discreet filtration systems being not as efficient or safe for the fish, and the more powerful ones being more expensive or visible.

My advice has been and always will be put the fish first, then worry about looks afterward.

What is best for your pets?

In the end, a healthy, well-filtered aquarium will support healthy, happy goldfish and save you extra work. ?

What Do You Think?

Do you wonder if your goldfish have enough filtration to balance out your water changes?

Have a question about how a certain filter works, or a preference for your tank?

Then please do leave your comment below.

4.5 90% from 13 ratings
Rating 4.5 90%


  1. Christina Murders December 24, 2017 at 11:13 pm - Reply

    I currently have a 10gal tank i am in the process of upgrading. What can I pair with my HOB filter to keep ammonia down? I change the tank every other day about 50%, my tank is technically over stocked (3 goldies). Currently running a fish-in cycle (first time goldfish owner).

    Rating: 4.5
    • Pure Goldfish
      Pure Goldfish December 31, 2017 at 9:47 pm - Reply

      Sponge filters could be a good pair 🙂

  2. Karen M. March 9, 2018 at 1:48 am - Reply

    A 55 -60 gallon tank and Eheim canister filter and your HOB with 30%-40% water changes every 3 days and bare bottom- you will be all set!

    Rating: 5
    • Pure Goldfish
      Pure Goldfish March 11, 2018 at 10:25 pm - Reply

      Those frequent water changes enable goldfish to grow exponentially 🙂

  3. Penny March 23, 2018 at 9:06 pm - Reply

    I have two goldfish (about 2.5 inches) in a 60 litre tank with a sponge filter. My fancy fish has been sitting in a bottom corner of the tank which I realise is the least affected by the vibration of the filter. I decided to turn the filter off an hour ago and it’s as if the fish has had a new lease of life. I don’t care about the noise of the filter myself but I now think that the vibration has been a nightmare for the poor fish. What now?

    Rating: 5
    • Pure Goldfish
      Pure Goldfish March 25, 2018 at 8:23 pm - Reply

      Is your sponge filter really vibrating that much? Maybe try a new brand. I’d keep an eye on your bottom sitting fish just in case this is a health problem.

  4. Tom March 28, 2018 at 2:59 am - Reply

    Very nice article. Thanks

    Rating: 5
    • Pure Goldfish
      Pure Goldfish April 1, 2018 at 10:31 pm - Reply

      Thanks, Tom!

  5. Steve June 4, 2018 at 5:46 pm - Reply

    Got a 28 gallon Aqua one tank with three Shubinkins and a few rosy shiners in it, would love to put in a trickle filter but no stores in NE england sell them.

    Rating: 4.5
  6. Suraj Chauhan June 7, 2018 at 7:53 am - Reply

    Hello I am planning to keep 9 gold fish of 2 inches in my 3ft long 2 ft height and 1 ft wide aquarium which filters should I use for my fancy gold fish

    Rating: 5
    • Pure Goldfish
      Pure Goldfish June 9, 2018 at 5:32 pm - Reply

      A wet/dry filter setup is ideal for medium to large size tank 🙂

  7. lou June 17, 2018 at 2:17 pm - Reply

    9 goldfish in a tank that size will result in stunting. Goldfish will grow to 18 inches. To say they will grow to the size of the tank is partially true. Their outside will grow to the size of the tank but their insides continue to grow. Thus becoming stunted. They will then die.
    If your tank will take say 30 inches then you should only have 2 goldfish, allowing them to grow to their full size.

    Rating: 3
    • Pure Goldfish
      Pure Goldfish June 18, 2018 at 5:31 pm - Reply

      Yes, good point, Lou!

  8. Rebecca July 27, 2018 at 2:16 pm - Reply

    We have a 75 gallon with fancy goldfish,2 hob filters and I have a wave maker in one corner to avoid stagnant spots. Our fish have grown and are thriving after over a year. We feed them peas and gel food. Other than them nibbling the plants and miss balls occasionally we have had no issues with filtration,water pH levels,tank is clear,fish are super active.

    Rating: 5
    • Pure Goldfish
      Pure Goldfish July 29, 2018 at 1:25 am - Reply

      Thanks for sharing, Rebecca!

  9. Jewel September 3, 2018 at 1:42 pm - Reply

    I have two 65 gallon HOB filters and two sponge filters going on in my 55 tank. I have 7 goldfish in the tank( yes I know over stocked by a lot I am in the process of moving) I checked the water everything was at 0 and ideal levels. I don’t see any waste anywhere. When I turn off my filters and stir the sand up nothing there either. I am just wondering if I should do the water change ? A big one small one ? I just want to make sure these guys are all good.

    Rating: 5
    • Pure Goldfish
      Pure Goldfish September 3, 2018 at 9:48 pm - Reply

      0 nitrates might indicate an uncycled tank. Every established tank should have some low nitrates unless you are doing water changes daily and feeding really sparingly. But changing more water is usually a good idea regardless 🙂

  10. Brittany Fitzpatrick September 15, 2018 at 6:12 pm - Reply

    Thanks for all of the great information! I’ve been reading up as much as I can!

    I have a 20-gallon long tank that previously housed an axolotl. My HOB has kind of kicked the bucket after 4+ years of business with the axie, and I would like to house a black moor and an orange fancy (or telescope) goldfish together in the tank. My plan is to paint the underside of the tank, so it has a bare bottom, but with a sandy look (and no space taken up by substrate), and add some freestanding plastic or silk plants for decor/hiding behind. Is the size of the tank acceptable for these two fish together? If so, I am looking at getting a new Fluval HOB – but I am unsure as to which size would make the most sense for goldfish. I know some people prefer to get one that has a higher tank size rating, so it has more cleaning power, but was wondering what your recommendation would be! Thanks!

    Rating: 5
    • Brittany Fitzpatrick September 15, 2018 at 8:37 pm - Reply

      Sorry – an orange FANTAIL or telescope

      Rating: 5
    • Pure Goldfish
      Pure Goldfish September 17, 2018 at 4:29 pm - Reply

      You’re welcome! The tank size is adequate. The smallest size is perfect for your size tank. Too high of rating will stress the fish, as fancies don’t like tons of current.

  11. Veronica November 12, 2018 at 4:05 am - Reply

    Is there ever a thing that there’s too much filtration? I’ve really been thinking about making the move from hang on to a canister. Any thoughts? I’m feeding my goldfish a lot and having to clean their tank daily. I want them to be large I have a 55 gallon that holds 3 goldfish, one is still a baby and a 20 gallon for my one fish and a 40 for my axolotl

    Rating: 5
    • Pure Goldfish
      Pure Goldfish November 13, 2018 at 6:49 pm - Reply

      You can never have too much filtration.

      You can have too much current.

      If you have slim-bodied fish, more current is not usually an issue.

      Fancies don’t do well with strong current.

      Hope this helps 😉

  12. Norman J. Szylakowski February 6, 2019 at 8:24 pm - Reply

    I have a Fluval C-4 for a 56 column tank and four fancies. I am thinking of investing in another C-4 or would that be overdoing it.

    Rating: 4.5
    • Pure Goldfish
      Pure Goldfish February 6, 2019 at 9:20 pm - Reply

      How effective is your single C4? If you have issues with ammonia/nitrite spikes chances are you need more. Another reason to upgrade would be if you want to add more fish and need to support a heavier bioload. Having another filter allows for more filtration media, which if you use the right kind might help in gaining control over nitrates. So it depends on what you want to achieve 🙂

  13. Erika March 15, 2019 at 4:45 pm - Reply

    I am completly new to this. I have a 10 gal tank i am setting up to get one fancy gold fish. What would be a good starter filter for me?

    • Pure Goldfish
      Pure Goldfish March 15, 2019 at 4:55 pm - Reply

      For my 10 gallon fancy tank I use this canister filter. Going on 2 years now and it has done a great job. You can adjust the flow rate by turning the valve.

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