Kamptonema formosum is a filamentous cyanobacterium commonly found in freshwater environments and moist terrestrial habitats. It forms long, unbranched filaments composed of cylindrical cells with a firm cell wall. The cells contain chlorophyll-a and phycobiliproteins, giving them a greenish-blue coloration. Kamptonema formosum may produce specialized nitrogen-fixing cells called heterocysts. Reproduction occurs through fragmentation of filaments, and sexual reproduction via conjugation is also possible. This cyanobacterium contributes to nutrient cycling and plays a role in ecosystem processes in its habitats.