Closterium praelongum is a green algae characterized by its elongated, curved cell shape, typically ranging from 100 to 600 micrometers in length. Each cell contains one or more large, band-shaped chloroplasts that extend longitudinally along the cell’s body. Enclosed within a flexible and transparent cellulose cell wall, Closterium praelongum reproduces through both asexual means via binary fission and sexual reproduction involving the formation of gametes and subsequent zygote formation. It inhabits freshwater environments such as ponds, lakes, and slow-moving streams, often adhering to submerged surfaces. Closterium praelongum contributes to ecosystem dynamics through photosynthesis and serves as a vital component of the aquatic food chain, utilizing a gliding motion facilitated by a gelatinous sheath surrounding the cell for limited movement.