Brazilian Micro Sword

About

Brazilian micro sword is the flat-bladed grass of the genus Lilaeopsis: a marsh plant from Argentina, Paraguay and south-eastern Brazil that grows submersed as a turf of narrow, slightly flattened blades, two or three of them rising from each node of runners that creep along and just under the substrate. Grown well it is a coarse-grained lawn rather than a fine one - mid to dark green, blades individually visible, dense enough to hide the sand, with fresh tufts breaking through a couple of centimetres ahead of the established ones. Height is the tell of how it is being kept: the databases print 3-6 cm, Tropica's own card promises the 4-7 cm 'lawn effect' only at high light intensity, and Dennerle's up-to-8 cm is what an under-lit tank produces. Keeping it alive is easy; making it carpet is not, and that is exactly where the sources split. Tropica and Dennerle file it under easy, Flowgrow and Aquasabi under medium, and both are describing something real: it rarely dies and it frequently refuses to close. Light is the pivot, and the sources agree here more than their icons suggest. Flowgrow rates it medium to high, Dennerle's own profile high to very high, Aquasabi states that a dense lawn forms only under very intensive light - and Tropica, whose light icon is the lenient medium (0.5 W/L), prints on that same card that the lawn effect comes only at high light intensity. Only the rating is lenient, not the advice; we follow the demanding side, because light that fails to reach the substrate does not kill this plant - it stretches it. Under-lit, or quietly shaded by taller neighbours, the blades grow tall and stringy and the carpet stays patchy with bare substrate showing between the tufts. CO2 is the contested field, and we call it required rather than optional because no source publishes a way to close the lawn without it: Flowgrow prints 10-40 mg/l, Dennerle 10-20, Tropica 6-14, Aquarium Breeder calls CO2 a huge requirement for a dense carpet, and Dennerle's own text concedes that without CO2 and strong light growth is slower and less dense. The plant will survive a low-tech tank - that much is genuinely easy, and it is what the 'easy' labels are measuring - but the lawn you bought it for may simply never close. It is a slow starter regardless: expect weeks of apparent standstill after planting before the first runners appear, and several months to a finished carpet even when you buy several pots and split them into many plugs. That slowness is also its algae problem, because blades growing this slowly under strong light are prime real estate once light runs ahead of nutrients, so light has to be matched with CO2 and ferts rather than merely turned up. Two of its failure modes are mechanical rather than chemical. Potted and tissue-culture stock arrives in the emersed form and melts after planting; do not bin it, the submersed blades regrow. And until the runners knit, the clumps are barely anchored: freshly planted tufts detach and float free, and a fish, a shrimp or one pass with the gravel vacuum will lift them out, so keep the vacuum off the grass and expect to replant strays for the first few weeks. The green in our photo is not conditional: this species has no red form, and no amount of iron, intense light or starved nitrate will colour it - unlike Helanthium tenellum in our catalogue, whose narrow-leaved form genuinely does turn red under exactly those conditions. Here it is density and height that vary, not colour. On the shop bench the confusion is mostly one plant under two labels: stock sold as Lilaeopsis novae-zelandiae is almost always this species, because the true New Zealand plant is probably not in aquarium culture at all and part of that trade may be L. ruthiana. Lilaeopsis attenuata is a third label on the same pots, and unlike the other two it belongs to a real and separate South American species, which is why we do not carry it as a synonym. We keep the New Zealand label as its own catalogue entry, New Zealand micro sword, because it is what the shelf actually says - but the pot under it usually holds this plant. The field test is tactile: roll a blade between finger and thumb, flat is brasiliensis, round is the novae-zelandiae form, which also runs taller, to about 12 cm. Against the other grasses in this catalogue, dwarf hairgrass (Eleocharis parvula) has round, needle-fine leaves that come up singly and spread far faster; dwarf sagittaria (Sagittaria subulata) has thick fleshy blades over 5 mm wide that run to 40 cm; and Helanthium tenellum's blades are paper-thin, 1.5-2 mm, and widest above the middle.

Care

Split the pot or cup into small clumps of a few blades and plant them 2-3 cm apart with tweezers in sand or fine gravel, 1-1.5 cm deep with the crown at the surface - scattered clumps knit into a lawn faster than one dense block. Give it the brightest open spot in the foreground and keep taller plants from closing over it. Run CO2: it survives without, but no source reports a closed carpet without it, and iron and NPK have to arrive steadily alongside. Expect to replant strays for the first few weeks - until the runners knit, tufts detach and float loose, so keep the gravel vacuum off the grass and blow debris out of it at water changes instead. Trim it like a lawn: a hard cut across the top forces compact regrowth. It prefers the cool end, 18-24 C rather than 27-28 C, so it does well in an unheated room-temperature tank and poorly in a discus-warm one.

Diet

Feeds from both ends - roots into the substrate, where a nutrient soil or root tabs pay off because each tuft is anchored by fine dense roots, and blades taking iron, nitrate, phosphate and potassium from the water. Flowgrow's working column is roughly 10-50 mg/l NO3, 0.1-3 mg/l PO4, 5-30 mg/l K and 0.01-0.5 mg/l Fe. Starved, it does not yellow dramatically; it simply stops spreading and lets algae take the blades.

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Frequently asked questions

What water parameters does a Brazilian Micro Sword need?

Brazilian Micro Sword does best at 15–28 °C (59–82.4 °F), pH 6–8 and a general hardness of 2–20 °dGH.

Where should Brazilian Micro Sword be placed in the aquarium?

Brazilian Micro Sword works best in the foreground and reaches around 8 cm.

Is the Brazilian Micro Sword suitable for beginners?

Brazilian Micro Sword sits in the middle of the difficulty scale — manageable for a careful beginner who has done the reading, but it has specific needs worth researching first.

Sources

• Lilaeopsis brasiliensis - Flowgrow Wasserpflanzen-Datenbank
• Lilaeopsis brasiliensis (040) - Tropica Aquarium Plants
• Lilaeopsis brasiliensis - Aquasabi
• Lilaeopsis brasiliensis - Dennerle Plants (UK shop listing)
• Brazilian grass plant, Lilaeopsis brasiliensis - Dennerle pot (Garnelio, carrying the full Dennerle Plants profile)
• Lilaeopsis novae-zelandiae - Flowgrow Wasserpflanzen-Datenbank
• Lilaeopsis brasiliensis - Wikipedia
• Lilaeopsis attenuata (Hook. & Arn.) Fernald - Wikispecies (mirroring POWO/Kew)
• Brazilian Micro Sword care guide - Aquarium Breeder
• Getting microsword to carpet - The Planted Tank Forum
• Akvariuminis augalas Lilaeopsis Novae-Zelandiae (syn. L. brasiliensis) - Akvazoo.lt
• Lilaeopsis brasiliensis - Akvariumų studija (akvariumustudija.lt)