With its small, round leaves barely a few millimeters in diameter, Hemianthus callitrichoides, one of the smallest aquatic plants in existence, spreads across the bottom of the aquarium.
The plant isn't fussy, but it does require good lighting, added CO2, water circulation, and fertilizer to thrive.
Often, small bubbles or beads of oxygen settle on the surface of the plants, giving this ground cover a very lively appearance.
Planted in small clumps a few centimeters apart, it can completely carpet the tank floor in no time. If the conditions aren't right, you can try Micranthemum 'Monte-Carlo', which requires much less care. Trim it regularly, otherwise the lower parts may die and lose their grip on the substrate.
Hemianthus callitrichoides is an attractive foreground plant for small aquariums. It originates from Cuba, west of Havana.