The best canister filters for beginners

A canister filter sits under the tank, holds lots of filter media and runs almost silently. For a tank of 40 gallons or more, or a planted tank you want to look clean, it's often the best filter you can buy. Here's how to choose one, what size to get, and how to set it up without leaks.

How these picks were chosen: each one is a widely sold, well-established product that does its job simply, which matters most when you're starting out. Paid links: if you buy through the Amazon links on this page, I earn a small commission at no extra cost to you.

In my own tanks I mostly run Fluval filters and Aquarium Co-Op sponge filters.

Quick picks

Sizes are the makers' own ratings. For a heavily stocked tank or messy fish like goldfish and plecos, go one size up.

Do you need a canister filter?

Most beginner tanks don't. A hang-on-back filter is cheaper, easier to clean and works well up to about 55 gallons. See the best aquarium filters. A canister makes sense when:

• Your tank is 55 gallons or bigger, where a hang-on-back struggles.
• You want a quiet filter, for a bedroom or living room.
• You want a clean look, with only two thin pipes in the tank. This matters most in a planted or aquascaped tank.
• You keep messy fish, like goldfish, plecos or cichlids, and want lots of media.

The downsides: canisters cost more, take longer to clean, and a loose hose can leak water onto the floor.

What size canister do I need?

Aim for a filter that moves 4 to 6 times your tank's volume every hour. A 55 gallon tank wants a filter rated for about 220 to 330 gallons per hour. Canister ratings are measured with empty media baskets, so the real flow is lower. That's why buying for a slightly bigger tank than yours is the safe choice. Not sure how big your tank is? Use the aquarium volume calculator.

The filters

Fluval 07 series (107, 207, 307, 407)

The most common canisters in pet stores. They come with media, have a push-button primer so you don't have to start the siphon by mouth, and a lever that shuts off both hoses so you can lift the canister out for cleaning. The 107 suits a 20 or 29 gallon, the 207 a 29 to 40, the 307 a 40 breeder or 55, and the 407 a 55 or 75.

EHEIM Classic

A design that has barely changed in decades: a plain canister with a pump on top and very few parts to wear out. It's known for running for years. Priming takes a little more work than the Fluval, and you may want to buy shut-off valves for the hoses. The Classic 2213 suits tanks up to about 66 gallons.

Budget canisters

Brands like SunSun and Polar Aurora sell canisters for much less, many with a built-in UV light. They work, but quality varies more and replacement parts are harder to find. If you choose one, check the hose connections often in the first weeks. See budget canister filters.

Setting up a canister without leaks

1. Rinse the media in tap water before the first use only. After that, always rinse it in old tank water.
2. Put the canister below the tank, usually inside the stand. It works by gravity siphon and must sit lower than the water.
3. Cut the hoses to length with no kinks or sags, and push them fully onto the fittings.
4. Check the lid's rubber ring is clean and seated before you close the clips.
5. Prime it with the primer button or by filling it with water, then plug it in.
6. Put a towel under it and check for drips after an hour and again the next day.

Cleaning a canister filter

Most canisters need cleaning every 1 to 3 months, when the flow drops. Close the valves, lift the canister to a bucket, and rinse the sponges gently in tank water you took out during a water change. Never wash the media in tap water or replace it all at once, because that's where your good bacteria live. Wipe the lid's rubber ring and put a thin layer of the maker's lube or plain silicone grease on it. See how to clean an aquarium filter.

Canister filter questions

Can a canister filter go on a small tank?

Yes, a small one like the Fluval 107 works on a 20 gallon. Below that, a sponge or hang-on-back filter is simpler.

Do I still need an air stone?

Usually not, if the outflow ripples the surface. Point it slightly up, or use a spray bar along the top. See fish gasping at the surface.

Is a canister better at keeping water clean?

It holds more media, which helps, but no filter replaces regular water changes.

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