Can Amazon Sword and Water Onion Grow Together?

Amazon Sword and Water Onion share a workable water window around 22 to 28 °C, pH 6 to 7.5, and 2 to 15 dGH.

Both plants are comfortable in freshwater, so salinity is not a meaningful obstacle.

Both prefer moderate flow, so circulation can be planned as one steady pattern.

Both fit moderate light and no added CO2, so one lighting and CO2 plan can support the pair.

Both plants naturally lean toward the background, which is why spacing, pruning, and final mature size matter more than they do in a more staggered planting mix.

Amazon Sword reaches about 50 cm tall by 40 cm wide, while Water Onion reaches about 150 cm tall by 30 cm wide. Use those mature sizes for the layout, not the small nursery portions you bring home.

Shade is worth watching, but it is usually manageable through trimming and a little spatial separation.

Amazon Sword is typically rooted in substrate with nutrient-rich substrate preferred and feeds mainly as a root feeder. Water Onion is typically bulb / tuber on or partly in substrate with nutrient-rich substrate preferred and feeds mainly as a root feeder. That difference can make the pairing easier to arrange than two plants fighting for the exact same root or attachment zone.

They can share the space, but the scape will stay cleaner if you leave more room than the labels alone might suggest.

Both plants have moderate growth, low maintenance, and beginner difficulty. That makes the maintenance rhythm predictable: watch for crowding, remove old leaves, and avoid letting one clump shade the other for weeks at a time.

The practical watch-outs are that both plants tend to work in the background, so spacing matters more than usual; and that you will want to leave more room than usual for mature spread and routine thinning; and that the layout needs a little thought so one plant does not slowly dim the other.

The strongest reasons to try the mix are that they share a workable temperature window around 22 to 28 °C; and that their flow preferences sit close enough to tune one layout around both plants.

Use this pairing when you want two plants that can share one routine without forcing a compromise at every step. It is strongest in tanks where mature spacing is planned before the plants fill in.

The simple success test is whether both plants still look healthy after the faster grower has been trimmed several times. If one keeps declining after routine care, the layout is probably asking too much of it.