Dwarf baby tears (HC Cuba)
Hemianthus callitrichoides
advanced careOverview
Dwarf baby tears (Hemianthus callitrichoides), universally known as HC Cuba, is the tightest, most sought-after foreground carpet in the hobby — a dense mat of tiny round leaves just a few centimetres tall. It is also one of the most demanding plants you can grow. Unlike a hardy rhizome plant, HC Cuba is a genuine high-tech species: it wants strong light, injected CO2 and clean, stable water, and it punishes neglect by melting. If you are new to planted tanks, cut your teeth on easier carpets like staurogyne repens or micro sword first.
Planting & placement
HC Cuba is a pure foreground carpet. Buy it as tissue-culture cups or emersed pots, rinse it, and split the mat into many small clumps with tweezers. Plant each clump firmly into a fine, nutrient-rich aquascaping soil — a proper substrate is not optional here, as the plant feeds heavily through fine roots. Space the clumps a couple of centimetres apart so they spread to meet. Our how to plant aquarium plants guide covers the tweezer technique, and the dry-start method is a popular way to establish HC before flooding.
Light, CO2 & ferts
This is where HC Cuba lives or dies. It needs high light reaching the substrate — see best light for a planted tank — and pressurised CO2 held stable through the photoperiod. Skimp on either and the carpet stretches upward, thins, or rots. Dose a complete water-column fertilizer so growth never stalls; our best fertilizer picks suit high-tech tanks. Keep good flow so CO2 and nutrients reach the low leaves.
Propagation & problems
Once established, HC Cuba propagates itself by sending out horizontal runners. To spread it, lift a section of mat, cut it into pieces and replant them into gaps. The classic problems are melting (a CO2 or light shortfall, or an unstable young tank) and the whole carpet detaching and floating up before it has rooted. Plant deep, keep early flow gentle, and resist the urge to disturb it. Because the carpet sits in bright light close to the substrate, algae can move in fast on weak growth — see how to get rid of aquarium algae and keep the plant growing strongly, which is the best algae defence.
Dwarf baby tears (HC Cuba) — frequently asked questions
Does HC Cuba really need CO2?
For a proper flat carpet, yes. Hemianthus callitrichoides is one of the most CO2-hungry carpeting plants there is. Without pressurised CO2 it tends to grow tall and leggy, thin out, or melt — it is not a low-tech plant.
Why is my dwarf baby tears melting or floating away?
Melt usually follows a light or CO2 shortfall, or a big swing after planting. Carpets also lift when the mat has no roots into the substrate yet — plant small clumps deep, keep flow gentle at first, and don't disturb it for a few weeks.
How do I get HC Cuba to carpet flat instead of growing up?
Give it strong light, stable CO2 and lean but present fertilisation, and trim the tops regularly. Frequent trimming forces horizontal runners, which is what knits the carpet together across the substrate.
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