Aquarium Internal Filters

These Internal filters fit inside the aquarium or fish tank, fixing to the glass with rubber suckers. They usually contain a sponge that works both mechanically and biologically, to remove ammonia and solid waste. They are ideal for smaller aquariums, or those that are not heavily stocked with fish. Popular makes include the Fluval U Series from Hagen, Betta Internal Filters, Oase Bioplus Thermo