Euglena heimii is a freshwater microorganism belonging to the genus Euglena. It features an elongated, spindle-shaped cell with a flexible pellicle. The cell contains chloroplasts for photosynthesis, an eyespot for light detection, and a single flagellum for movement. It stores paramylon as a carbohydrate reserve. Euglena heimii inhabits nutrient-rich freshwater environments, where it contributes to ecosystems through photosynthesis and may exhibit mixotrophic behavior.