PlantFreshwaterEasy
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Hemianthus callitrichoides 'Cuba'
Hemianthus callitrichoides "Cuba"
Tiny creeping plant from Cuba, famously known as 'HC' or 'Cuba'. Demands high-intensity light, fine aquasoil, and steady CO2 to form a flawless carpet.
Water Temperature
18 - 28 °C
pH Value
5 - 7
Water type
Freshwater
Light
High
CO2
Medium - High
Expected height
3 cm
GH
0 - 20 dGH
KH
0 - 18 dKH
Species description
Geographical Origin and Habitat: Native to Cuba, where it grows in shallow rocky streams and on wet shores. It experiences seasonal variations, thriving in emersed muddy habitats and submerged riverbeds.
Taxonomy & Genetics: Belonging to the family Linderniaceae, it was discovered by Holger Windeløv. Colloquially known as HC or 'Cuba', it is genetically adapted to environments with intense tropical light and flowing water.
Physical Structure: Features extremely compact, creeping, and branching stems. The roots are very fine but secure. The leaves are among the smallest of any aquarium plant, measuring only about 1 mm, arranged oppositely.
Color & Texture: Vibrant, bright emerald green. The texture of the carpet is exceptionally dense and low-growing, making it the most coveted plant for Iwagumi layouts.
Care, breeding and tankmates
Lighting & CO2: Requires high-intensity lighting (RGB LEDs preferred) to promote horizontal, creeping growth. Constant CO2 injection (20-30 mg/L) is vital for its long-term survival and propagation.
Nutrition & Substrate: Requires a fine-grained, fertile substrate (such as aquasoil powder) for its delicate roots. It is a heavy consumer of iron and potassium, requiring regular liquid fertilization.
Water Chemistry: Prefers soft to medium-hard water with a pH of 5.0 to 7.0. Ideal temperatures range from 18°C to 28°C (64°F - 82°F). Sensitive to high salt content.
Space Management & Placement: Best placed in the foreground. Plant in small clumps spaced a few centimeters apart; they will grow together to form a uniform carpet.
Pruning: Trim regularly with curved aquascaping scissors. If the carpet grows thicker than 2 cm, the bottom layers will rot due to lack of light, causing the entire lawn to float.
Risks & Diseases: Vulnerable to filamentous algae and cyanobacteria if water flow is inadequate or if nutrient balances are off. Iron deficiency causes rapid leaf yellowing.
Geographic Origin and Distribution
Native to Cuba, where it grows in shallow rocky streams and on wet shores. It experiences seasonal variations, thriving in emersed muddy habitats and submerged riverbeds.
Origin
Central America and Caribbean
Plant profile
- Placement
- Foreground
- This plant is strictly a foreground species, prized for creating the most compact and detailed carpets in aquascaping. It must be planted where it receives the absolute maximum amount of light, completely unshaded by hardscape or taller plants. Hemianthus callitrichoides "Cuba" can also be grown beautifully cascading over the edges of rocks or driftwood. It is highly favored in both large display tanks and meticulous nano aquascapes.
- Botanical form
- Stem
- Possessing some of the smallest leaves of any aquarium plant, Hemianthus callitrichoides "Cuba" consists of delicate, creeping stems lined with tiny, round leaves. The foliage is a brilliant, fresh green that creates a highly textured surface. Its root system is extremely fine and shallow, making initial planting a delicate process. Over time, it forms a mat several layers thick.
- Growth
- Medium
- Under the high light and CO2 conditions it demands, Hemianthus callitrichoides "Cuba" grows at a moderate to fast pace. It spreads laterally via creeping stems that hug the substrate closely. If conditions are suboptimal, its growth stalls entirely and it quickly becomes susceptible to algae. Frequent trimming encourages faster, denser lateral growth and prevents it from uprooting itself.
- Substrate
- High
- To thrive, Hemianthus callitrichoides "Cuba" must be planted in a very fine, nutrient-dense powder-type aqua soil that accommodates its extremely small root structure. A substrate layer of 3 to 4 centimeters is sufficient for these tiny roots to grip the soil, preventing the plant from floating away. A continuous and rich supply of substrate nutrients is absolutely vital to power its rapid, low-growing lateral spread across the aquarium floor.
- Column fertilization
- Required
- Because its root system is so fine, Hemianthus callitrichoides "Cuba" relies heavily on absorbing nutrients directly from the water column. A strict regime of liquid EI (Estimative Index) or similar comprehensive dosing is highly recommended. Adequate potassium is crucial to prevent the older leaves from developing pinholes. Heavy CO2 injection is non-negotiable for lush, vigorous growth.
- Root fertilization
- Recommended
- While it draws significantly from the water column, a fine-grained, nutrient-rich powder-type aquasoil is vital for Hemianthus callitrichoides "Cuba". The fine grains allow its incredibly small, delicate roots to anchor securely. Without a soft substrate, the creeping stems will float away before they can attach. Root tabs are less effective due to how shallow the roots penetrate.
- Trimming
- Regular
- Regular and aggressive trimming is the secret to a healthy Hemianthus callitrichoides "Cuba" carpet. Use curved spring scissors to trim it very low, almost back to the substrate. If allowed to grow too thick, the bottom layers will receive no light, die off, and the entire carpet will detach and float to the surface. Clean up all floating trimmings immediately to prevent them from clogging filters.
- Propagation
- Cuttings
- Propagation is simple but tedious. Hemianthus callitrichoides "Cuba" is propagated by dividing portions of the carpet into small plugs and planting them in a grid pattern. As the stems grow horizontally, they naturally produce roots at each internode. Ensuring the plugs are planted deeply enough so they aren't uprooted by water flow or livestock is the primary challenge.
- Sensitivity
- HIGH
- This is a famously sensitive plant that acts as an indicator species for aquarium health. Hemianthus callitrichoides "Cuba" will immediately show signs of distress if CO2 drops, light is insufficient, or flow is poor. It is highly susceptible to being smothered by diatoms or cyanobacteria in immature tanks. A stable, fully cycled environment with excellent water circulation is mandatory.
- Layout role
- Nano, Foreground, group
- The layout role of Hemianthus callitrichoides "Cuba" is to provide the ultimate fine-textured foreground carpet. It gives a profound sense of scale, making rocks look like massive mountains and the aquarium feel much larger than it is. It is the gold standard for Iwagumi aquascapes requiring meticulous detail. Its cascading growth habit also softens the transition between substrate and hardscape.
Image gallery
Licensed images linked to the species or, when marked, to the closest representative taxon.
Related species
Recommendations grouped by close relatives, companion choices, and similar care.
