Navicula menisculus is a diatom species characterized by its elliptical or lanceolate valves that resemble a crescent or boat shape with slightly protracted ends. The valves feature fine, parallel, uniseriate striae, often adorned with punctate or lineolate ornamentation. Like other Navicula species, N. menisculus possesses a central raphe that runs longitudinally along the valve. It typically ranges from 20 to 60 micrometers in length. Found in various freshwater habitats such as lakes, ponds, and rivers, Navicula menisculus can exist both as planktonic and benthic forms, contributing significantly to the ecological dynamics of aquatic ecosystems.