Araguaia Hygrophila

About

Araguaia Hygrophila entered the hobby with a false passport: it was sold as Hygrophila sp. 'Araguaia', supposedly collected at Brazil's Rio Araguaia, until Dieter Wasshausen of the Smithsonian Institution identified it as the Asian species Hygrophila lancea. Where in Asia is still loose - Tropica only hedges that there are many signs pointing to Japan and Hong Kong, Dennerle records South East Asia, and shop listings still print the Brazilian story - but the trade name stuck. It is a dwarf, freely branching stem plant with very narrow, strap-like leaves that colour reddish brown over a conspicuously paler midrib. Almost everything flattering about it is conditional. The low creeping habit is: the shoots run sideways and knit into a loose carpet only under strong light, and in weaker light the plant climbs instead, to around 30 cm. The colour is: the red-brown tones need high light, CO2 in the region of 25-40 mg/l and steady iron and micronutrient dosing, and under less it sits dark green to brownish-green and sheds its lower leaves. Bare stem bases are not only a lamp problem - crowding does the same thing, and a clump shaded by taller neighbours goes bald at the bottom however bright the tank is above it. Water is the gate the catalogue's other hygros do not have: every carbonate figure published for this plant stops at 7 dKH and the shops describe its hardness ceiling simply as soft, where Temple Plant, Dwarf Hygrophila and Water Wisteria all run to 15-18 dKH. Hard tap water is a real reason this species dies where those three thrive, and 'Sarawak' - a different trade form of the same botanical species, rated to 12 dKH - is the one sold for it. It ships in its emersed form, so the old foliage melts away before the slender coloured underwater leaves appear. How quickly it then fills in is disputed: one source calls it a rather slow grower in contrast to most other Hygrophila, another states flatly that its growth rate is average for the genus, and a third calls it moderate to fast. In the shop, do not confuse it with 'Chai', a pink-and-white variegated sport of this very plant that is rated difficult and slow; from small Rotala species tell it by the pale midrib on strictly linear leaves and by a colour that peaks at red-brown, never bright Rotala red.

Care

Not a beginner Hygrophila, despite one supplier rating it easy. It wants high light, injected CO2 and steady iron and micronutrient dosing; without them it stretches, fades to green-brown and drops its lower leaves. The stricter limit is carbonate hardness - the published bands stop at 7 dKH and pH 7, so hard tap water has to be cut with RO or rainwater before this plant is worth buying, and the 'Sarawak' form, not this one, is what handles harder water. Plant several stems as a clump in the front midground and keep the space around it clear, because crowding strips the stem bases as effectively as dim light. Pinch the tips to force branching, and expect the emersed leaves it is sold with to melt before the submerged ones appear. Published heights run from a trimmed 5-20 cm to 30 cm left alone, so regular cutting back is what keeps it low.

Frequently asked questions

What water parameters does a Araguaia Hygrophila need?

Araguaia Hygrophila does best at 18–30 °C (64.4–86 °F), pH 4.5–7 and a general hardness of 0–8 °dGH.

Where should Araguaia Hygrophila be placed in the aquarium?

Araguaia Hygrophila works best in the midground and reaches around 30 cm.

Is the Araguaia Hygrophila suitable for beginners?

Araguaia Hygrophila is a demanding species best attempted with some experience — it needs stable, closely watched conditions to thrive.

Sources

• Flowgrow Wasserpflanzen-Datenbank - Hygrophila lancea "Araguaia" (primary)
• Flowgrow Aquatic Plant Database - Hygrophila lancea "Araguaia" (EN mirror)
• Tropica - Hygrophila lancea 'Araguaia' (plant 4758)
• Aquasabi - Hygrophila lancea "Araguaia"
• Dennerle Plants - Hygrophila lancea 'Araguaia' (30259)
• Buce Plant - Hygrophila Araguaia (Hygrophila Lancea)
• Aquasabi - Hygrophila lancea 'Chai' (lookalike)
• The 2Hr Aquarist - How to grow Hygrophila sp. chai (habit and lookalike)
• Flowgrow - Hygrophila lancea "Sarawak" (lookalike)
• Aragvaja - Lietuvos Vikipedija (Lithuanian river name)