The best canister filter for most tanks between about 60 and 300 litres is a mid-size model with push-button priming, shut-off valves and a pre-filter you can clean on its own, sized to move about ten times your tank's volume every hour. Smaller tanks, planted displays and big cichlid tanks each suit a different type, so this page picks by type rather than naming one winner.
This is a short list of five canister types, numbered and kept in the same order, each with the one thing it's best for and an honest drawback. None of the slots is sponsored.
How to read this page
The picks are product types, not filters I've tested side by side. I run AllPondSolutions external filters on two of my tanks (more on that below); where I name any other model, it's an example a cited reviewer recommends or a manufacturer's own rating, not a claim from my own cabinet. Prices change often, so check the retailer's page.
The short answer
Match the filter to the tank and what lives in it:
- Most tanks from about 60 to 300 litres (15–80 US gallons): a mid-size canister with priming and shut-off valves — pick 1.
- A tight budget, a lightly stocked tank, or a second filter: a budget canister — pick 2.
- A planted tank where you want the heater out of sight: a canister with a built-in heater — pick 3.
- A small tank, about 40–130 litres: a small canister — pick 4. Under about 100 litres, a hang-on-back filter is often enough.
- A big or heavily stocked tank (large cichlids, goldfish): a high-flow, high-capacity canister — pick 5.
A canister — called an external aquarium filter in the UK — sits in the cabinet, out of sight, and holds far more media than a filter that hangs on or sits in the tank. The 2Hr Aquarist calls it the best all-rounder for tanks above 50 litres, and the trade-off is cost and more parts to set up.
The picks
Quick comparison
| # | Canister type | Best for | Typical tank size | Key feature to check | Relative cost |
|---|---|---|---|---|---|
| 1 | Mid-size canister with priming and valves | Most tanks | ~60–300 L | Shut-off valves, primer, separate pre-filter | Mid |
| 2 | Budget canister | Light stock, second filter | Varies | Noise and build quality | Low |
| 3 | Canister with built-in heater | Planted tanks, clean displays | Varies by model | Heater wattage for your tank | Mid to high |
| 4 | Small canister | Small tanks | ~40–130 L | Flow suits a small tank | Low to mid |
| 5 | High-flow, high-capacity canister | Big or heavily stocked tanks | Large tanks | Flow you can turn down; cabinet space | High |
"Relative cost" is a rough ranking, not a price. Tank sizes are approximate; check the rating for the exact model you buy.
How I chose
Five things separate the best aquarium canister filter for your tank from a frustrating one:
It's sized for the turnover you need. The 2Hr Aquarist's target for planted tanks is about ten times the tank's volume per hour. As an example, a 200-litre tank at ten turnovers needs about 2,000 litres an hour. Aquarium Store Depot warns that the flow printed on the box is measured with no height to pump against, and drops once the filter sits in a cabinet below the tank — so check the manufacturer's head-height figures, and go a size up for heavily stocked tanks.
It primes easily. The 2Hr Aquarist says a priming function lets you start the filter without starting the water flow by hand, and that most modern filters have one.
It has shut-off valves. Quick-release valves let you disconnect the canister from its hoses without spilling water, according to the 2Hr Aquarist. You can fit your own if a filter doesn't come with them.
The pre-filter comes out on its own. The 2Hr Aquarist recommends a pre-filter compartment you can clean without taking the main filter apart, because a filter that's easy to clean gets cleaned. Its examples of filters that have one are OASE's BioMaster series and larger Aquael models.
It's quiet and well built. A canister often lives in a living room. The 2Hr Aquarist says better filters run with minimal noise and that poorly built ones carry more risk of leaks and breakdowns.
Free tool
Canister ratings are given in litres or gallons per hour. Measure your tank once and work out how much water it really holds before you compare flow ratings.
Aquarium volume calculator →Each pick, honestly
1. Mid-size canister with priming and shut-off valves — best overall. This is the canister most tanks should start with: enough media for a normal community or planted tank, valves for clean maintenance, and a primer so start-up doesn't involve a siphon. As one example, Aquarium Store Depot rates Fluval's 07-series canisters as its best-value pick, and Fluval's own page for the smallest 07 model lists AquaStop valves and a redesigned primer. Drawback: a canister has more hoses, seals and parts than a hang-on-back filter, and the 2Hr Aquarist says it is more complicated to set up.
2. Budget canister — best budget. If money is tight, a cheaper canister still gives you the media volume and hidden hoses. Aquarium Store Depot's budget pick is the SunSun, which it describes as cheap with a lot of features for the money, and good enough for a beginner tank, a quarantine setup or a second filter. Drawback: in the same review it was the loudest filter tested, the reviewer flagged build-quality concerns, and he reports measurable flow loss on a comparable unit after about a year and a half.
3. Canister with built-in heater — best for planted tanks and clean displays. A planted tank looks better without a heater stuck to the glass. OASE says the integrated heater in its BioMaster 2 Thermo reduces in-tank equipment and protects fish from direct contact with it; the 250 model is rated for aquariums up to 250 litres and comes with a 150 W adjustable heater. Aquarium Store Depot names this filter its top pick overall and the second quietest it tested. Drawback: it costs more than a standard canister, and the same review notes it can be hard to find in local stores.
4. Small canister — best for small tanks. For a tank of roughly 40–130 litres where you still want the filter hidden, a small canister fits under the tank without overpowering it. As an example, Fluval rates its 107 canister for 10–30 US gallons (40–130 litres). Drawback: less media than bigger canisters, and on a tank under about 100 litres a hang-on-back filter is, in the 2Hr Aquarist's words, easy and cheap — so a small canister mainly pays off on a planted or CO2 tank where you want hidden kit.
5. High-flow, high-capacity canister — best for big or heavily stocked tanks. Large cichlids, goldfish and big tanks produce more waste than a mid-size canister handles comfortably. Fluval's FX6, for example, is rated for tanks up to 400 US gallons (1,500 litres) with a pump output of 925 US gallons (3,500 litres) an hour, and starts itself without manual priming. Drawback: that much flow is wrong for a small or gently planted tank, and the box takes a lot of cabinet space.
My own tanks
My 150-litre mbuna tank runs an AllPondSolutions EF2 external filter alongside an under-gravel filter that I set up as an anoxic filter. My Juwel Trigon 190 runs an AllPondSolutions 2000EF, working alongside the internal filter built into the tank. In its early planted phase, the Trigon ran on that built-in Juwel internal filter.
My 90-litre planted community tank has no canister. It runs an OASE BioPlus 100 internal filter and an under-gravel filter set up as an anoxic filter, under a layer of Seachem Flourite with a top layer of fine white sand mixed with pebbles.
That's a less common choice for a planted tank. The 2Hr Aquarist says under-gravel filters can work but aren't popular in planted aquariums, because pulling debris into the substrate means more compaction and detritus to clear, and that they aren't ideal with aqua soils. If you're setting up a new planted tank, a canister is the simpler route — which is why it's the page you're reading.
Whatever filter you choose, don't start it empty. Every tank I've cycled has had fish in it, and since my first tank I've seeded each new filter with media from an established tank plus a bottled bacteria starter — mostly FritzZyme 7 now. The cycling guide covers how.
What you can skip
- Buying on the box's flow figure alone. Aquarium Store Depot says the headline rating is measured with no height to pump against; check the head-height figures instead.
- A canister that only just matches your tank. The same reviewer recommends going one size up for heavily stocked tanks.
- Rinsing biological media under the tap. Aquarium Store Depot traces crashed tanks to exactly this. If you clean bio media at all, swish it in tank water taken out during a water change.
- A built-in UV as the reason to buy. Aquarium Store Depot found the UV on its budget pick underpowered. Buy a canister for its filtration, not the extras.
- A canister on a small, lightly stocked tank if you don't need hidden kit. A hang-on-back filter does the job for less money.
Put it to work
Not sure a canister is the right type for your tank? The best aquarium filter page compares all five filter types. Running CO2? The aquarium CO2 system guide explains the inline atomisers and reactors that fit on a canister's outflow. Choosing a light at the same time? See the best planted aquarium light shortlist and the planted aquarium lighting guide. And if the tank is brand new, make sure it's cycled before fish go in.