Filter unit for aquariums (1), designed to allow easy maintenance by an operator, comprising, in a container (100):
- a filtering path, extending between an entrance (2a) and an exit (2b) of fluid, for the circulation of a flow of liquid;
- a mechanical filter (4) positioned along said filtering path to intercept the flow of liquid circulating therein, said mechanical filter (4) having an entrance surface (4a) orientated upstream of the filtering path;
- at least one scraper member (5a) designed to perform cleaning of the mechanical filter (4), detaching impurities accumulated on said entrance surface (4a) by means of scraping; and
- means for promoting a relative motion between scraper member (5a) and mechanical filter (4) causing said scraping of the entrance surface (4a) of the mechanical filter (4).