Aquarium Filters
A filter keeps the water clean and houses the bacteria that make your tank safe for fish. Browse what we carry, then ask us which size and flow suit your tank.
Filters in stock
Live inventory from our store. Selection changes as shipments arrive.
Oase Biomaster Thermo External Filter with Heater
Biomaster Thermo External Filter
Oase Biomaster External Canister Filter
Biomaster Thermo External Filter
How to choose an aquarium filter
Size the filter to the tank
Choose a filter rated for your tank size or a bit larger. An undersized filter struggles to keep up with fish waste, especially in heavily stocked tanks.
Mind the flow
Strong flow suits active fish like danios, while bettas and long-finned fish prefer gentle flow. If a filter is too strong, a baffle or a different outlet position can help.
Protect your beneficial bacteria
Most of a filter's biological work happens on its media. Rinse media in old tank water rather than tap water, and avoid replacing all of it at once.
Related: Choosing the best filter, The nitrogen cycle, How often to change water.
Common questions
How often should I clean my filter?
It depends on the filter and how heavily the tank is stocked. When flow slows noticeably, rinse the mechanical media in a bucket of old tank water and leave the biological media alone as much as possible.
Do I need a filter for a small tank?
Yes. Even small tanks need filtration and a cycled system, with gentle flow for fish like bettas.
Can a filter replace water changes?
No. Filters process waste but do not remove nitrate. Regular partial water changes are still important.
Not sure what fits your tank?
Bring your tank size and what you keep in it, and we will help you choose.