HC Cuba

Quick facts

Max height

4 cm

Growth rate

moderate

Difficulty

advanced

Placement

foreground

Propagation

fragmentation

Water parameters

Temperature

20–28°C

pH

5.5 to 7.0

Hardness

0 to 10 dGH

Light and nutrients

Lighting

very high

CO2

required for healthy growth

Substrate

nutrient rich

Feeding

feeds from both water column and roots (liquid ferts plus root tabs)

Substrate

What this plant roots into (or attaches to). The substrate affects both plant nutrition and water chemistry; see each linked page for full effects.

This plant feeds primarily from the water column, so substrate choice matters more for its fish-tank compatibility than for plant nutrition.

With fish

Plant-eating fish

safe with plant-eating fish (tough leaves or unpalatable)

Diggers (corydoras, loaches)

may get uprooted by active diggers

Root-disturbing fish

sensitive to root disturbance, plant where roots stay undisturbed

Habitat

Native to Cuba, growing in and along shallow, calcareous (hard-water) streams and wet rocky areas. The species (Hemianthus callitrichoides, commonly abbreviated HC or HC Cuba) produces some of the smallest leaves in the aquarium plant hobby: individual leaf pairs are 2–4 mm across on thin, creeping stems. This miniature scale makes it the gold standard for foreground carpeting in competitive aquascaping, creating a lush, verdant lawn effect that no other plant replicates at the same scale. HC Cuba was introduced to the aquarium hobby in the early 2000s by Tropica (the Danish aquatic plant company) after being collected in Cuba, and rapidly became one of the most popular and sought-after plants in the Nature Aquarium style. The plant's small size and demanding requirements make it a benchmark species for judging a planted tank setup's quality.

Care notes

The most demanding common carpeting plant. Requires high light (80+ PAR at substrate level), pressurized CO2 injection (25-35 ppm), and nutrient-rich substrate to carpet successfully. Without all three, the plant grows slowly, develops gaps, and eventually recedes. This is not a low-tech plant; attempts to grow HC Cuba without CO2 almost always fail. Plant small portions from tissue culture cups 1–2 cm apart across the foreground, pressing them firmly into fine-grained substrate (aquasoil or sand). Rich substrate is critical; the tiny roots feed actively. Growth under optimal conditions is moderate: the carpet fills in over 4-6 weeks, with creeping stems branching and overlapping to form a dense mat. Trim with sharp scissors to maintain a uniform height of 1–2 cm. The carpet lifts off the substrate if gas bubbles (from pearling or substrate decomposition) accumulate underneath; press it back down or use a substrate pin. Algae is the primary threat: BBA, green hair algae, and cyanobacteria can overwhelm the slow-growing carpet if CO2, light, and nutrients fall out of balance. Stable, consistent dosing is more important than high dosing. Temperature: 20–28°C. Soft to hard water (the species comes from calcareous water and actually prefers moderate to high GH, unlike many demanding plants). A rewarding plant for experienced keepers with high-tech setups.

Further reading

• CO2 injection for planted tanks: what it costs, what it does, and when to skip it