Species guide
HC Cuba / Dwarf Baby Tears Care Guide
Aquatic plant
HC Cuba (Hemianthus callitrichoides ‘Cuba’) is the tiny-leaf carpet people mean when they say dwarf baby tears. It is harder than Monte Carlo: more light, injected CO₂, and no patience for dirty substrate. If your tank is low-tech, buy Monte Carlo instead.
- Hard carpet
- High light + CO₂
- Tiny leaves
- Not Monte Carlo
Quick facts
| Light | High PAR at substrate; dim desk LEDs fail |
|---|---|
| CO₂ | Required for a closed carpet — optional only if you accept melt |
| Temp | 20–26 °C; warmer + weak CO₂ → melt |
| Substrate | Fine aquasoil; sand alone rarely holds a lawn |
| Planting | Small clumps 1–2 cm apart, not one giant wad |
| Trim | Scissor the top; do not rip the mat |
| Difficulty | Advanced beginner / high-tech |
| Height | 1–3 cm if healthy |
Overview
Shops label almost any tiny green mat “HC.” True Cuba has smaller leaves than Monte Carlo (Micranthemum tweediei). Monte Carlo forgives medium light. Cuba does not. If you want a first carpet, start with Monte Carlo or dwarf hairgrass.
Triangle: light / CO₂ / fert · CO₂ hub · PAR / watt tool. Melt playbook: carpet melting. Budget lawn: 20-gal carpet. High-tech path: low vs high-tech.
How to actually get a lawn
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Step 1
Confirm you bought Cuba, not Monte Carlo
Cuba leaves are pin-head small. Monte Carlo is rounder and larger. Care is not interchangeable.
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Step 2
Inject CO₂ before you plant a full foreground
Dry-start or emersed cups still need CO₂ when you flood. No gas = melt in 10–20 days.
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Step 3
Plant many tiny plugs, not one brick
1–2 cm gaps. A single wad rots in the middle. Press soil around roots.
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Step 4
High PAR at the sand, not just at the surface
Measure or use a real planted LED. See the light calculator.
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Step 5
Trim the canopy, keep the runners
Weekly once it knits. Pull algae with a turkey baster, not your fingernails through the mat.
Common problems
Whole patch melts after flooding
Why: Emersed tissue + no CO₂ / dirty flood.
Fix: Leave crowns; restore CO₂; see <a href="{EN['mc_melt']}">carpet melt</a>.
Grows up instead of out
Why: Not enough light at substrate.
Fix: Lower the lamp or raise PAR. Do not add more hours.
Holes + diatoms on new tissue
Why: Unstable tank or low fert.
Fix: Cycle first. Lean daily fert once light/CO₂ are on.
Never knits, just sits
Why: Planted too deep or too sparse + low GH.
Fix: Replant shallower; add more plugs; check GH ~4–8.
Tank mates
Gear for this species
Landen Aqua Soil Substrate for Natural Planted Aquarium, Plant or Shrimp Stratum, Clay Gravel and Stable Porous Substrate for Freshwater Aquarium, Black Color 40lbs
Substrate vàng chuẩn Iwagumi / Nature Aquarium.
20 gallon carpet budget — HC Cuba is a high-tech lawn, not a low-tech starter carpet
FAQ
Is HC Cuba the same as Monte Carlo?
No. Monte Carlo is Micranthemum tweediei — easier, larger leaf. Cuba is H. callitrichoides — tinier, pickier.
Can I grow HC without CO₂?
Almost never as a closed carpet. You may keep a sad clump. Buy Monte Carlo or hairgrass instead.
Dry start or wet start?
Dry start helps beginners knit. You still need CO₂ the day you flood.
How much light?
High at substrate. If stems in the back are pale but HC is stretching, the lamp is too far.
Will shrimp eat it?
Adult cherries nibble biofilm, not a healthy mat. Amano in huge numbers can pick it apart.
Good first high-tech plant?
Only after you can hold CO₂ green on the drop checker all photoperiod. Otherwise start Monte Carlo.
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