Rotifers: Microscopic Filters
These tiny aquatic animals (just 0.2mm) clean water by consuming microbes and organic particles. A single rotifer clears 1-2mL of microbe-rich water daily, maintaining healthy aquatic environments for fish or plants. Their asexual reproduction ensures population stability even in small habitats. Space station experiments confirm normal reproduction in microgravity. Automated nutrient systems could maintain their food supply with minimal human intervention, ideal for labor-limited Mars colonies.