Last Updated: September 18, 2026
The wrong part can fit poorly even within one brand, so compatibility matters more than any ranking. The best replacement impeller for canister filters is the exact OEM part for your model and generation, because Fluval uses different part numbers such as A20109 for the 107/207 and A20208 for the FX2/FX4, and they are not interchangeable.
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By David Nguyen
Quick answer: For most people in 2026, the best replacement impeller for canister filters is the A20109 — our #1 rated choice. See the full ranked comparison, alternatives and buying advice below.
How to Choose a Replacement Canister Filter Impeller
Confirm the model and OEM part number before buying, then check what the assembly includes and what it costs against replacing the whole motor head. Marketplace titles often blur generations, so the safest approach is to read Fluval’s own compatibility listing for your exact filter rather than trusting a similar-looking part.
Match the Exact Filter Model
Fluval assigns impellers per model line, so the A20109 is listed for the 107 and 207 only, not the 307 or 407. Ordering by your filter’s exact model number is the first check, because a part that looks similar can differ in shaft length or magnet, and the wrong one may not seat correctly.
Start with the printed model on your canister, then confirm the matching part on Fluval’s page for that unit. Replacement-part listings across marketplaces frequently mix the 05, 06 and 07 generations, so the model-first approach avoids buying a part built for a different series of the same brand.
Match the Exact OEM Part Number
Beyond the model, verify the OEM part code: A20149 fits the 307, A20169 fits the 407, and A20208 fits the FX2 and FX4. These numbers are specific, and even filters one step apart in the lineup use different impellers, so the code is the reliable identifier rather than a general brand match.
Write down your part number from the manual or Fluval’s product page before ordering. Because the 307 and 407 use distinct codes despite similar pricing, treating any Fluval impeller as universal is the classic mistake this check is designed to prevent for canister filter owners.
Check What the Assembly Actually Includes
The 07-series parts explicitly list a ceramic shaft and rubber bushing in the assembly, which matters because those components wear alongside the impeller. Knowing what is in the box tells you whether a single order restores the pump or whether you still need a separate shaft or bushing to finish the job.
Do not transfer that 07 wording to the FX A20208, which is listed as a magnetic impeller assembly with the shaft handled separately for the FX2/FX4. Read each part’s own contents rather than assuming every Fluval impeller ships with the same hardware set across every model line.
Compare Part Cost Before Replacing the Motor Head
Impeller prices in this lineup run from about $20.99 to $34.99, far less than a full motor head, so a diagnostic swap is usually the sensible first move. When a canister runs loud or weak, checking the impeller and shaft before replacing the whole unit often restores performance for a small outlay.
Make the replacement decision diagnostic rather than automatic: inspect for debris, cracked shafts or worn bushings first. A cheap part can fix a noisy pump, but if the motor itself has failed, an impeller alone will not help, so confirm the cause before ordering any replacement component.
Top Picks
These four OEM impellers cover the common Fluval canisters, chosen for exact compatibility rather than a performance ranking. All were listed by Fluval as current and in stock, with the 07-series trio at one price and the FX part higher. Confirm your model and part code before ordering any of them.
| Product | Best For | Key Spec | Watch Out For |
|---|---|---|---|
| A20109 | Fluval 107/207 | OEM; shaft + bushing | Not 307 |
| A20149 | Fluval 307 | OEM; shaft + bushing | 307 only |
| A20169 | Fluval 407 | OEM; shaft + bushing | 407 only |
| A20208 | Fluval FX2/FX4 | OEM impeller assembly | Do not use for FX5/FX6 |
A20109: For Fluval 107 and 207
The A20109 is the OEM impeller for the Fluval 107 and 207, priced around $20.99 and including a ceramic shaft and rubber bushing. That bundled hardware makes it a complete restore for a worn or noisy 07-series pump, so a single order usually returns the filter to normal operation.
The watch-out is that it fits the 107/207 only, not the 307, which uses a different code. Confirm your printed model number before ordering, because the visual similarity between 07-series parts is exactly what leads buyers to install a part meant for another canister in the line.
A20149: For Fluval 307
The A20149 is the exact OEM impeller for the Fluval 307, also around $20.99 and listed with a ceramic shaft and rubber bushing. It is dedicated to the 307, so buyers stepping up from a smaller canister should not assume their previous part carries over to this model.
Its watch-out is that it is 307-specific: the 407 uses the separate A20169 despite both currently sharing the same price. Matching the code to the printed model avoids the common mix-up between adjacent Fluval canisters that look and cost alike but take different impellers.
A20169: For Fluval 407
The A20169 is the OEM impeller for the Fluval 407, priced near $20.99 with the ceramic shaft and rubber bushing included. As the largest of the round-body canisters here, the 407 has its own dedicated part, so the replacement must be ordered by this exact code rather than a neighboring one.
The watch-out is straightforward: it is 407 only. Because the 307 and 407 share pricing but not parts, this is the pairing most often confused, so verify the model on your unit before buying to avoid installing an impeller built for the smaller 307 canister.
A20208: For Fluval FX2 and FX4
The A20208 is the magnetic impeller assembly for the Fluval FX2 and FX4, priced around $34.99, higher than the 07-series parts. That is about $14 or roughly 66.7% more than the $20.99 impellers, though a higher price does not translate into proportionally higher performance across different models.
Its critical watch-out is that it does not fit the FX5 or FX6, which use the A20206 part instead. Do not treat the FX line as sharing one impeller, and confirm whether your unit is an FX2/FX4 or an FX5/FX6 before ordering, since the codes are distinct.
Frequently Asked Questions
Owners commonly ask whether parts cross between models, whether adjacent canisters share an impeller, and which code fits the FX units. The answers below stay with Fluval’s OEM listings, because the recurring source of returns is a part bought for a similar-looking canister from a different series or generation.
Can I Use a 107/207 Impeller in a Fluval 307?
No. The 107 and 207 use the A20109, while the 307 uses the A20149, so the parts are not interchangeable even though the canisters share a family resemblance. Installing the wrong one risks a poor fit and does not restore the pump correctly.
Always match the code to your printed model. The safest routine is to confirm the OEM part number on Fluval’s page for your exact unit before ordering, rather than assuming a part from a smaller canister will drop into the 307.
Do the Fluval 307 and 407 Use the Same Impeller?
No. The 307 takes the A20149 and the 407 takes the A20169, even though both currently list at about $20.99. Identical pricing between adjacent canisters is exactly what leads buyers to assume a shared part, so the codes matter more than the cost here.
Order by the model-specific code from Fluval’s listing for your filter. Because these two are the most commonly confused, double-checking the printed number on your canister before purchase prevents installing an impeller designed for the neighboring model in the line.
Which Impeller Fits an FX4?
The FX4 uses the A20208 magnetic impeller assembly, which is also listed for the FX2 and currently runs around $34.99. That part is specific to the FX2/FX4 pairing and is priced above the round-body 07-series impellers in this lineup.
Do not carry it over to the larger FX units. Confirm your model is an FX2 or FX4 before ordering, since the FX5 and FX6 take a different part, and the FX family does not share a single universal impeller across every model.
Is the FX5/FX6 Impeller the Same as FX4?
No. The FX5 and FX6 use the A20206, while the FX2 and FX4 use the A20208, so the two groups take different parts. Fluval’s official FX5/FX6 price is about $70.99, though availability has sometimes shown out of stock on its site.
Match your exact FX model to its code before buying. Treating the whole FX line as sharing one impeller is a common error, so confirm whether you own an FX2/FX4 or an FX5/FX6 and order the corresponding OEM part accordingly.
Final Thoughts
The best replacement impeller for canister filters is always the exact OEM part for your model and generation, verified by part number rather than by appearance or price. Confirm the code on Fluval’s listing for your unit, check what the assembly includes, and make the swap a diagnostic step so a small, correct part restores the pump reliably.
Ready to decide? Our #1 pick for 2026 is the A20109.
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