Hemianthus callitrichoides 'Cuba'
The smallest aquatic plant in the hobby. Forms a fine-textured emerald carpet that pearls aggressively under CO₂. High-tech only, without CO₂ and 60+ PAR it melts. Dry-start method is the most reliable path to a complete carpet.
Dwarf Baby Tears (HC Cuba) (Hemianthus callitrichoides 'Cuba') is a carpet / stem aquatic plant for the foreground of a planted tank. It reaches 1–3 cm under good conditions and grows at a medium rate. Light: high. CO₂: required. Target 20–26 °C, pH 5.5–7.0, and 1–10 dGH. Substrate: Fine, active nutrient-rich substrate (ADA Amazonia or similar). Propagate via cuttings / runners spread horizontally.
Care at a glance
The smallest aquatic plant in the hobby. Forms a fine-textured emerald carpet that pearls aggressively under CO₂. High-tech only, without CO₂ and 60+ PAR it melts. Dry-start method is the most reliable path to a complete carpet.
By Mike ElmiraUpdated 2 min read
Part of our complete guide to the planted aquarium.
Hero photo by Ranjith-chemmad · CC BY-SA 4.0 · Wikipedia
The parameters that decide whether dwarf baby tears (hc cuba) fits in your tank.
Linderniaceae
Carpet / Stem
Foreground
Fine, active nutrient-rich substrate (ADA Amazonia or similar)
Cuttings / runners spread horizontally
Damp seasonal seepage zones of Cuba and Central America
Cuba
Tank-mate safety and the species this one is documented to thrive (or fail) alongside.
Hard-won lessons from the tank.
Dry-start method (DSM) is the highest-success path: plant tiny clumps 2 cm apart on damp substrate, cover with plastic film to retain humidity, mist daily, run lights 8 hours/day. In 4–6 weeks you'll have a 90%+ complete carpet that transitions to submerged form when you fill the tank. Going directly submerged works but expects more failures and a 50%+ chance of redoing patches.
What can go wrong and how to spot it.
Failure modes, in order of how dramatic the fix is.
Pale: nitrogen + iron. Leggy upward growth: insufficient light (need 60+ PAR at substrate). Lifting carpets (detachment from substrate): root rot from CO₂ instability or substrate decay.
Hair algae is the single biggest killer. Stable CO₂ (no daily fluctuation) and conservative light hours during establishment (4–5 hours/day for the first month) prevent it. Once carpet is dense, hair algae rarely attaches.
The practical routine, read top to bottom.
Heavy CO₂ user; absolutely demands stable CO₂ at 30 ppm. Active nutrient substrate (ADA Amazonia, UNS Controsoil, Tropica Aquarium Soil). Macro and micro EI-style dosing.
Trim with sharp curved scissors every 2–3 weeks once carpet establishes. Trimming forces horizontal spread and triggers tighter compact growth. Vacuum trimmings IMMEDIATELY — floating fragments root randomly and create messy patches.
Where it comes from, how it behaves, and the variants you'll see at retail.
Where it lived before it came home.
Cuban wet meadows and streambanks. Naturally grows emersed in damp soil; the submerged form is a specialty aquarium-only morphology that doesn't occur in the wild.
Vigorous emersed grower — sold as tissue culture cups grown on damp media. Emersed form has slightly larger oval leaves; transitions to submerged via dry-start or controlled flooding.
Tiny white flowers emersed; never flowers submerged.
The named cultivars and the lookalikes worth flagging.
Only one form is sold under this name. 'Mini' and 'micro' labels in the trade are usually marketing — true HC Cuba leaves average 2–3 mm. Hemianthus glomeratus (formerly H. micranthemoides, 'pearlweed') is sometimes mislabelled and is much taller and easier.
Pearlweed (Hemianthus glomeratus) is the most common substitution — looks similar in the shop but grows 8–15 cm tall, not 1–3 cm. Glossostigma elatinoides is another common false-HC; it has larger oval paddle-shaped leaves.
Direct answers to the questions search engines and AI assistants surface most often about this species.
CO₂ requirement: required. Light requirement: high. Under stable injected CO₂ the plant grows at a medium rate.
Dwarf Baby Tears (HC Cuba) (Hemianthus callitrichoides 'Cuba') needs high light. Run a photoperiod of 6–8 hours; longer photoperiods invite algae unless CO₂ and dosing are dialled in.
Position: foreground. Substrate: Fine, active nutrient-rich substrate (ADA Amazonia or similar) It typically reaches 1–3 cm.
Propagation method: Cuttings / runners spread horizontally. Dwarf Baby Tears (HC Cuba) is a carpet / stem plant.
Target 20–26 °C, pH 5.5–7.0, and 1–10 dGH. Flow tolerance: low.
Difficulty: 5/5. Expert, narrow tolerances; not recommended until you've kept a stable tank for a year.
A planted tank is a system. Pair this plant with one entry from each other pillar to plan the whole scape.
