How do you grow AR mini in an aquarium? Plant AR mini (Alternanthera reineckii ‘Mini’) as small stems in a nutrient-rich substrate, give it medium to high light, and add CO2 and liquid fertilizer. Tropica says it grows compact and fairly slowly, and with careful trimming forms a red-violet carpet about 2 to 4 inches (5 to 10 cm) tall.
Key takeaway: AR mini is the dwarf cultivar of Alternanthera reineckii, a red aquarium stem plant. Tropica rates it medium light and medium CO2 (6 to 14 mg/L), with a height of 2 to 4 inches (5 to 10 cm) after two months. It says high light and CO2 improve growth and color. Trim often to keep it low and bushy.
| Need | What sources report | Source |
|---|---|---|
| Plant type | Stem plant; cultivar from tissue culture | Tropica |
| Height | About 2–4 in (5–10 cm) | Tropica |
| Growth rate | Medium; slower than full-size AR | Tropica |
| Light | Medium on Tropica’s scale; high light improves it | Tropica |
| CO2 | Medium, 6–14 mg/L | Tropica |
| Species range (AR ‘Red’) | 72–82°F (22–28°C), pH 5–8, soft to hard water | Dennerle |
| Propagation (species) | Tip cuttings and side shoots | Dennerle |
What Is AR Mini?
AR mini is the nickname aquarists use for Alternanthera reineckii ‘Mini’. Tropica describes it as a miniature version of the well-known Alternanthera with compact growth and a slower growth rate. It suits small tanks or the foreground of larger aquascapes, where its red to violet leaves contrast with green plants.
The species is in the amaranth family (Amaranthaceae) and comes from South America, according to Dennerle. The full-size red forms can reach about 20 inches (50 cm), so the mini form is the better choice when you want red color low in the tank. For the larger plant, see our Alternanthera reineckii guide.
- Role: foreground or midground accent, or a low red carpet.
- Color: red-violet in strong light; greener in weak light.
- Source: often sold as tissue culture cups.
How Do You Grow AR Mini in an Aquarium?
Plant it in small portions so each stem gets light. Tissue culture cups are free of snails and algae, but the plantlets are tiny. Rinse off the gel, split the clump into small bunches, and push them into the substrate with tweezers. A nutrient-rich substrate or root tabs help red stem plants settle in.
- Rinse the gel off the tissue culture plants.
- Split them into bunches of 3 to 5 stems.
- Plant each bunch about 1 inch (2 to 3 cm) apart with tweezers.
- Add root tabs if your substrate is inert.
- Keep taller plants from shading the group.
Expect slow growth at first. We have no published figure for how long it takes to establish, so judge by new growth at the tips.
What Light, CO2 and Fertilizer Does AR Mini Need?
Medium to high light, CO2 and steady nutrients. Tropica lists it at medium light (0.5 W/L on its scale) and medium CO2, and says high light and added CO2 improve growth and appearance. Dennerle says all red-leaved stem plants need good lighting, enough CO2 and nutrients in the water column, and lists 20 to 30 mg/L CO2 for its full-size AR ‘Red’.
- Light: medium at minimum; more light gives deeper red.
- CO2: about 6–14 mg/L or more; see our aquarium CO2 guide.
- Fertilizer: complete liquid fertilizer with iron; see our aquarium plant fertilizer guide.
- Water: the species tolerates 72–82°F (22–28°C) and pH 5–8 (Dennerle, for AR ‘Red’).
Why Is AR Mini Melting or Not Growing?
Most problems come from too little light, CO2 or nutrients. Dennerle’s guidance for red stem plants points to all three. Tropica notes that high light and CO2 improve its growth and appearance, so in weak light expect slower, greener and looser growth. In our experience, tissue culture plantlets are delicate, and some of the tiny original leaves may fade after planting while new tips form.
- Green, leggy growth: raise light and check CO2.
- Pale new leaves: check that you dose a complete fertilizer.
- Thin lower stems: reduce shade from taller plants and trim the top layer.
- No growth: check that roots have nutrients; add root tabs.
If you cannot add CO2, easier red or foreground options include Ludwigia and Staurogyne repens.
How Do You Trim and Propagate AR Mini?
Trim often to keep it low. Tropica says careful trimming creates a dense red-violet carpet about 2 to 4 inches (5 to 10 cm) tall. Dennerle lists tip cuttings and side shoots as the way to propagate the species. Each cut stem branches, so regular trims make the group bushier.
- Cut stems just above a leaf pair.
- Replant healthy tops as new stems in bare spots.
- Remove weak or bare lower stems if the group gets thin at the base.
For another red option, compare Rotala.
FAQ About AR Mini
Is AR mini easy?
It is moderate; it grows best with good light, CO2 and nutrients.
How tall does it get?
About 2–4 in (5–10 cm) with trimming.
Does it need CO2?
Tropica says CO2 improves growth; it is strongly recommended.
Why is it turning green?
Usually too little light.
How do I propagate it?
Replant tip cuttings and side shoots.
Is AR mini a carpet plant?
It can form a low carpet with careful trimming.
Sources
- Tropica Aquarium Plants — Alternanthera reineckii ‘Mini’
- Dennerle Plants — Alternanthera reineckii ‘Red’/22974)
- Photo credits (Wikimedia Commons, edited with titles): Alternanthera reineckii (2).JPG – Photo by V C Balakrishnan by V C balakrishnan (CC BY-SA 4.0); Alternanthera reineckii ‘Roseifolia’ 2023-07-30 01 by Agnieszka Kwiecień, Nova (CC BY-SA 4.0)