The best hang-on-back aquarium filters for 2026
A hang-on-back filter is the easiest upgrade for most tanks up to around 200 litres: it hooks over the rim, holds plenty of media and is simple to service. These are the HOB filters we'd actually put on our own tanks.
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Frequently asked questions
What size hang-on-back filter do I need?
Aim for a filter rated at roughly 4× your tank's volume in turnover per hour, and check the manufacturer's suggested tank size. On a HOB it's better to buy one size up and dial the flow down than to run a small filter flat out — you'll get more media and a bigger biological safety margin.
Are hang-on-back filters good for planted tanks?
For low- to medium-tech planted tanks, yes. The downside is surface agitation, which can drive off CO2, so if you're injecting CO2 lower the flow and aim the return along the surface rather than churning it. High-tech scapes usually move to a canister for that reason.
Do HOB filters need priming?
Most self-prime once you fill the reservoir and switch on — the AquaClear and Seachem Tidal both start themselves. If the tank level drops too far below the intake they can run dry, so keep your water topped up, especially in warm rooms with high evaporation.
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