Ammannia Crassicaulis

About

This is the plant most of the people who own it have never actually owned. Kasselmann's verdict, repeated by Flowgrow, is that most stems traded under the old name Nesaea crassicaulis are really Ammannia gracilis - so routinely that Flowgrow admits the photo on its own database entry may be showing the wrong species. Learn the tells before you pay. True A. crassicaulis is the paler of the two: yellow-green stems carrying red-brown, cognac-toned leaves that run from yellowish-green to a soft pale red, on a shoot 8-15 cm across. A. gracilis is the vivid one, brown-red above with a deep violet leaf underside, on a wider 12-20 cm shoot, and that violet underside is the single most reliable tell. So the catalogue photo is conditional twice over: the colour appears only under strong light, injected CO2 and low nitrate, and the picture may not even be this species. Anyone expecting fire-engine red is picturing gracilis - the real thing is warm cognac, never scarlet. In the wild it is barely an aquarium plant at all, but a marsh subshrub of African and Madagascan swamps, rice paddies and rivulets from Senegal to Kenya and south to Natal, reaching 50 cm emersed in seasonal wetlands. Do not file that 50 cm away as a bog plant's height and forget it: Tropica, aquarium-guide and aqua-fish all put the submersed stem at 30-50 cm as well, and Flowgrow's own height field simply reads 'up to 50 cm'. This is a back-of-the-tank plant, and it only works further forward if you commit to topping it every few weeks. How fast it gets there is contested - Flowgrow and Buce Plant say fast, Tropica, aquarium-guide and aqua-fish say medium, and the grower Florida Aquatic qualifies it as 'moderately fast under good conditions'; plan for medium and read that qualifier as the warning it is. Because the plant ships emersed-grown or in vitro, the first weeks decide everything. The emersed leaves melt off by design, and if CO2 and light are not already right when they go, the stem does not slow down - it stops. New tips come in small and pale, the bared lower stem starts to rot, and algae take what is left before the plant gets a second chance.

Care

Treat CO2 as the pass/fail condition, not fertiliser. Flowgrow puts the floor at 20-40 mg/l - the highest of any comparable stem plant - and Aquamoos independently says 20-30, while Tropica's 'medium' rating means 6-14 mg/l, a range that sits entirely below the others. Follow the higher figure. Pair it with genuinely strong light (roughly 50 PAR and up) and soft water: KH under 9 and pH under 7 are where this plant is comfortable, and it is fussier about carbonate hardness than most red stems. That pH ceiling is contested - aqua-fish publishes 6-8 and aquarium-guide 5.5-8.5 - but both of those read as generic tolerance boilerplate, while Flowgrow, Aquamoos and Buce Plant all stop at 7, so 7 is what we publish. The commonest failure has nothing to do with dosing. When light cannot reach the lower stem because the group is crowded or shaded, the bottom leaves blacken and drop, leaving bare stalks with a tuft on top; space stems 8-10 cm apart, thin the group, and keep some flow moving between them. Read the symptom instead of reaching for iron. Green instead of red usually means nitrate is too high - the best colour comes from low nitrate alongside high phosphate and micros. Stunted or twisted new tips mean CO2 is low or unstable, or trace elements are overdosed; surplus iron makes stems longer and the red duller, the opposite of the intent. Sudden mush is shock, never a deficiency. The emersed leaves it arrives with will melt off during conversion, and that is expected rather than a mistake. Top it at 25-30 cm and replant the cuttings - that trim is also the only thing that keeps a 50 cm stem usable anywhere but the back wall. And if what you bought is really A. gracilis - the odds say it is - you have more margin than this profile implies on hardness and pH: KH to 14 instead of 9, pH to 7.5. Not on CO2, though. The gracilis entry asks for 25-30 mg/l in its own text even where its table drops the floor to 10, so the gas bill is much the same either way.

Frequently asked questions

What water parameters does a Ammannia Crassicaulis need?

Ammannia Crassicaulis does best at 15–31 °C (59–87.8 °F), pH 5–7 and a general hardness of 0–12 °dGH.

Where should Ammannia Crassicaulis be placed in the aquarium?

Ammannia Crassicaulis works best at the back of the tank and reaches around 50 cm.

Is the Ammannia Crassicaulis suitable for beginners?

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

Sources

• Ammannia crassicaulis - Dickstängelige Nesaea - Flowgrow Wasserpflanzen-Datenbank (PRIMARY, German)
• Ammannia crassicaulis - Flowgrow Aquatic Plant Database (PRIMARY, English)
• Ammannia crassicaulis - Tropica Aquarium Plants (article 033B)
• Ammannia gracilis - Flowgrow Aquatic Plant Database (the plant actually sold as crassicaulis)
• Does my plant have a nutrient deficiency? - The 2Hr Aquarist
• AQUARIUM GUIDE - Nesaea crassicaulis - Dickstängelige Nesaea
• Ammannia crassicaulis - AQUAMOOS (German retailer)
• Ammannia crassicaulis Guill. & Perr. | Plants of the World Online, Kew Science
• Nesaea Crassicaulis Aquarium Plant - Buce Plant
• Nesaea crassicaulis - Care Guide (aqua-fish.net)
• Ammannia crassicaulis - Florida Aquatic Nurseries (commercial grower)
• Hygrophila polysperma - Flowgrow Aquatic Plant Database (boilerplate control test)