Nano Internal Filter: A Guide
A nano internal filter is a small submersible unit for tiny tanks, giving gentle flow and basic filtration for shrimp and bettas.
Overview
A nano internal filter is a miniature submersible filter that sits inside the aquarium, designed for very small tanks. It provides gentle flow and small media chambers, which suits shrimp, bettas and pico setups where a strong current would be harmful.
How it works
Internal filters operate inside the tank. Water enters through slits or a foam layer, passes through the filter media, and is returned to the aquarium. Depending on the model, flow is driven by a small powerhead or, in air-driven designs, by an airlift tube fed with bubbles from an air pump.
Filtration provided
These filters combine mechanical and biological filtration in a small package. Foam or media traps debris while also hosting nitrifying bacteria that convert ammonia and nitrite. They are best suited to small, lightly stocked tanks rather than heavily loaded systems.
Why gentle flow matters
Nano filters deliver low flow rates appropriate for small water volumes. This protects delicate inhabitants such as shrimp and long-finned bettas, which struggle in strong currents, and keeps the small tank from being over-circulated.
Powered and air-driven types
Some internal filters are driven by a small built-in powerhead that pulls water through the media. Others, such as sponge and corner filters, are air-driven: bubbles from an air pump rise through an airlift tube and lift water with them, drawing it through the foam. Air-driven designs run quietly and produce very gentle flow, which suits shrimp and fry.
Maintenance
The foam or media is rinsed in old tank water rather than tap water so the bacterial colony survives. Because the chambers are small, cleaning is done regularly to prevent clogging that would cut flow in the limited volume.