Amazon Sword Care Guide

Amazon sword (Echinodorus grisebachii) is a large rooted rosette from South America and the standard background plant for community tanks that have substrate to spare. A mature specimen is roughly 40–50 cm tall and 30 cm across, which is a whole corner of a 55-gallon tank and simply too much plant for anything under about 20 gallons.

It is a root feeder, and that single fact drives everything else on this page. Where an epiphyte like java fern ignores root tabs entirely and lives off the water column, a sword does the reverse: liquid fertiliser alone will not keep it healthy, and a sword planted in inert gravel with no root nutrition slowly shrinks, pales and stalls no matter how much you dose the water.

It is still a beginner plant. It needs no CO2, tolerates ordinary community water, and grows steadily under medium light. The two things that catch people out are the dramatic melt after purchase and the assumption that it can be fed like everything else in the tank.

The instinct to pull the plant out and check on it is the thing to resist. A sword re-establishing its root system needs several weeks of being left alone; repeated uprooting is what actually kills the ones that die during conversion.

Push two root tabs under it at planting rather than waiting for the melt to finish. The new submersed leaves are grown on root nutrition, and a plant that has nothing to draw on produces a smaller, weaker second set.

Medium light suits it. Under a low-output LED a sword survives but stays small and grows slowly; under strong light it grows fast enough to need dividing and, without matching root nutrition, develops deficiency symptoms rather than more leaves.

Eight hours of moderate light is a sensible default. Because it is a background plant, watch for taller stems or floaters shading it out — a sword pushed into permanent shade thins from the outside in.

Not required. Amazon sword grows well in low-tech tanks and this is one of the reasons it is so widely sold.

Injected CO2 does help — leaves come in larger and the plant fills out faster — but it also increases nutrient demand, so a CO2 tank with no root tabs produces a hungrier, worse-looking sword than a low-tech tank with them.

This is a root feeder. Root tabs pushed into the substrate near the base are the primary feeding method, replaced roughly every two to three months, or a nutrient-rich substrate from the start. Liquid all-in-one fertiliser is a supplement here, not the main course — the exact inversion of the java fern rule, where tabs do nothing and liquid is everything.

The deficiency signals are specific enough to diagnose on sight. Holes appearing in older leaves point to potassium. Pale or yellowing new growth with the veins still green is iron chlorosis, and swords are notably iron-hungry. New leaves emerging small and stunted while the plant otherwise looks fine means it has run out of root nutrition — add tabs.

A sword in plain inert gravel with liquid dosing only is the single most common version of an unhappy amazon sword. It does not die; it just gets smaller every year.

Ordinary community water suits it: pH around 6.5–7.5, 3–15 dGH, and 22–28 °C. It is genuinely tolerant across that range and adapts to harder water than its Amazon origins suggest.

Temperature is not a limiting factor within the tropical band. Unlike java moss, there is no cool-water preference here — a sword is fine at discus temperatures and equally fine at 22 °C.

This is a background plant and a specimen plant, not something you buy three of. At 40–50 cm tall and up to 30 cm wide, one mature sword fills the back corner of a 4-foot tank and dominates anything smaller. In a standard 20-gallon it will reach the surface and shade most of the tank; below that, it is the wrong plant entirely.

It needs substrate depth as much as floor space — 6–8 cm at the planting site so the roots have somewhere to go. A sword in 2 cm of decorative gravel never anchors properly and gets pushed out by its own root growth.

Used well, the arching leaves are useful cover: angelfish and discus use the leaf mass as territory markers, and the shade under a mature rosette is a natural home for shade-tolerant plants like java fern and anubias.

Growth is moderate and steady — a new leaf every week or two once established, with the plant reaching full size over six to twelve months. Most of the maintenance is removing old leaves rather than shaping the plant.

Cut spent leaves at the base of the stalk, not partway up the blade. Older outer leaves yellow and are shed naturally; if you are removing several a week while new growth is also small, that is a root nutrition problem rather than normal turnover.

When the rosette starts crowding its neighbours, lift and divide the root mass rather than trimming leaves back — a sword cut short simply regrows to the same size and looks butchered in the meantime.

Amazon sword propagates through adventitious plantlets carried on flower stalks, which is a different mechanism from java fern’s leaf plantlets and from java moss’s fragmentation. A mature, well-fed plant throws a long arching stalk that travels across the tank and produces daughter plants along its length.

You cannot force it. Runners are a sign the plant has surplus energy, which in practice means good light and a well-stocked substrate. A sword that never sends out a stalk is usually a sword that is short of root nutrition.

Echinodorus grisebachii grows on the margins of Amazon rivers and in seasonally flooded ground, rooted in soft sediment that is rich in decaying organic matter. It spends part of the year emersed and part submersed, and it grows a different set of leaves for each state.

That is why the melt happens. A nursery grows it emersed because it is faster and cheaper, so the plant you buy is wearing the wrong leaves for the tank it is going into; the collapse you see in week two is the seasonal switch it makes every year in the wild, compressed and out of context.

Rooting in river sediment is also why root tabs matter so much. The plant evolved to draw nutrition from the ground it stands in, and an aquarium of washed inert gravel is a substrate with nothing in it — closer to a gravel bar than a floodplain.