Alternanthera reineckii
Alternanthera reineckii
Also known asscarlet temple · AR mini (small variant) · Alternanthera reineckii 'Roseafolia'
Water parameters
Light and nutrients
Substrate type: nutrient rich. Propagation: stem cuttings.
Substrate compatibility
| Substrate | pH effect | Nutrient load |
|---|---|---|
| Aquasoil (ADA Amazonia) | lowers pH | very high |
| Mineralized clay substrate (Seachem Fluorite) | neutral / inert | moderate |
| Dirted tank (mineralized topsoil) (DIY soil substrate) | slightly acidic | very high |
With fish
Origin and habitat
Native to South American river floodplains, where it grows primarily as an emersed (above-water) plant along muddy banks and in seasonally flooded areas. The species transitions to submerged growth when water levels rise, developing the deep red coloration that makes it popular in aquariums. Found across tropical South America from Argentina through Brazil. Several variants and cultivars exist in the aquarium trade: 'Mini', 'Rosanervig' (pink-veined), and the standard form. The emersed form is green to olive with reddish undersides; the submerged form develops intense red, purple, or magenta coloring under strong light. This is one of the most accessible red-leaved aquarium plants because it doesn't absolutely require CO2 injection, though color intensity improves dramatically with it. The genus Alternanthera includes many terrestrial species; only a few are aquatic.
Care notes
One of the few reliably red aquarium plants that doesn't demand CO2 injection, though it colors up much more vividly with CO2 and high light. Without CO2, expect brownish-red to burgundy rather than bright crimson. Under low light, the lower leaves drop and the stem becomes leggy and unattractive. Medium to high lighting (50+ PAR at substrate level) is the minimum for decent coloration. A nutrient-rich substrate or regular root tab supplementation helps because the plant is a moderate root feeder. Water column dosing of iron and micronutrients supports leaf color. Growth rate is moderate; trim and replant tops every 3-4 weeks to maintain bushy growth. The bottom portions of untrimmed stems become bare as lower leaves are shaded out. Propagation is by cuttings: cut the top 10–15 cm and replant directly into substrate. The cut stem usually produces side shoots. Avoid planting in deep shade behind taller plants; the red coloration requires direct light. CO2 at 20-30 ppm combined with high light produces the most intense color. In low-tech setups, place it directly below the light source and keep it trimmed short.