Internal Filters

Aquarium filters in general help generate flow, absorb substances that causes turbidity, and enrich the water with oxygen. Beneficial bacteria that settles within the unit’s filter media help to break down and remove waste from aquarium inhabitants. Internal filters are suitable for small aquariums and can be used for paludariums. These filters are placed inside the aquarium, usually in a corner. Internal filters can also be used as a secondary filter, or if there is no space outside the aquarium.  A key advantage is that no visible tubing connections interfere with the aquarium's overall aesthetic. 

OASE’s BioCompact and BioPlus internal filter series are characterized by discreet design options that are ideal for keeping focus on your aquarium’s beauty. The filters’ EasyClean features and advanced designs are perfect for maintaining a clean and healthy ecosystem for your fish and plants. OASE’s Thermo line of BioPlus filters have the added feature of an integrated heater. By integrating the heater into the filter the amount of additional equipment seen in the aquarium is reduced.

TIP! The basis for the selection of an aquarium filter is the size of the aquarium, measured by the amount of water. In general, it is better to choose an oversized filter system than a small one. 

TIP! Be patient... 
Important microorganisms that biologically clean the water settle on the filter foams in your aquarium filter. These microorganisms feed on minute particles that we perceive as debris - a new or recently cleaned filter only attains its full performance capacity gradually; the microbiology must first establish itself.



The BioCompact line of internal filters are designed to be discreetly installed horizontally or vertically. BioCompact uses biological, mechanical, and chemical filtration for optimal water quality and clarity, and the diffuser with adjustable flow control provides added aeration.

25 50
Suitable for aquariums up to, max. 10 gal 15 gal



The BioPlus line of premium internal corner filters uses biological, mechanical, and chemical filtration for optimal water quality and clarity. The integrated diffuser with adjustable water flow nozzle allows for uniform surface movement, prevents formation of biofilm, and provides added aeration.

BioPlus / BioPlus Thermo
50 100 200
Suitable for aquariums up to, max. 15 gal 30 gal 55 gal