Nitzschia filiformis is a diatom species characterized by its long, narrow, and often slightly sigmoid-shaped cells. The silica cell walls (frustules) have fine, parallel striae and a raphe system positioned along the valve margin for movement. In valve view, the cells appear slender with tapered ends, while in girdle view, they appear even narrower and filamentous. Nitzschia filiformis serves as a primary producer in aquatic ecosystems and is valuable for assessing water quality and environmental conditions due to its distinctive morphology and ecological role.