Echinodorus opacus Care Guide
Echinodorus opacus is a compact, slow-growing South American sword with thick dark-green leaves, well suited to the midground of soft-water aquariums.
Compiled by Aquairi from published sources · Published · Updated
Overview
Echinodorus opacus is a sword plant in the family Alismataceae, native to southeastern Brazil. It forms a compact rosette of thick, dark-green oval leaves and stays smaller than many of its relatives. Growth is slow and the plant rarely flowers in the aquarium, which together with its modest size makes it a stable midground rosette.
Taxonomy
- Family: Alismataceae
- Genus: Echinodorus
- Scientific name: Echinodorus opacus
Habitat
The species is recorded from southeastern Brazil, in the states of Paraná and Santa Catarina. Echinodorus are marginal plants of tropical and subtropical South American wetlands that grow either fully submersed or partly emersed, depending on water level.
Tank requirements
- Temperature: 22-28 °C (72-82 °F)
- pH: 6.0-7.5
- GH: 4-14 °dGH
- Lighting: medium to high
- CO2: not required
- Growth rate: slow
- Maximum height: about 25 cm
- Placement: midground
Planting and care
As a rosette sword with a substantial root system, it should be planted in a nutrient-rich substrate or supplied with root tabs in inert substrate. It is easy and undemanding, comparable to slow plants such as Anubias, and grows in low-tech tanks; added CO2 encourages faster growth. The plant takes up significant nitrate and shows fairly good resistance to algae.
Propagation
Echinodorus species propagate vegetatively. In opacus this occurs through adventitious plantlets and by division of the rootstock; daughter plants are separated once they have their own roots and replanted.
Propagating Echinodorus opacus (Opacus Sword)
Overview
Echinodorus opacus is a compact South American sword that grows as a rosette. Like other Echinodorus (Amazon swords), it can grow emersed, with floating leaves, or seasonally submersed, and its leaves range from linear through lanceolate to ovate. It is a heavy root feeder that wants a deep, nutrient-rich substrate.
Propagation Method
There are two reliable routes. First, adventitious plantlets: submersed inflorescences (flowering stems) produce baby plants instead of flowers, and these daughter plants can be separated once rooted. Second, division: an established rosette can be split through the crown and rhizome into separate plants. Grown emersed in humid conditions the plant flowers and sets seed, but in the aquarium the plantlet and division routes are the practical ones.
Step-by-Step
- Wait for a flowering stem to arch out; submersed, it forms plantlets at its nodes rather than flowers.
- Let each plantlet develop several leaves and its own roots before separating it.
- Pinch or cut the plantlet from the stem and plant it in nutrient-rich substrate, keeping the crown above the substrate line.
- To divide instead, lift a mature rosette and separate the crown/rhizome into sections, each with leaves and roots.
- Replant each section and press 2–3 root tabs into the substrate beside it.
Conditions for Healthy Growth
- Temperature: 22–28 °C.
- pH: about 6–7.5.
- Light: medium; good light supports underwater leaf growth.
- Substrate: deep and nutrient-rich; this is a heavy root feeder.
- CO2 is not required, but added CO2 often helps stronger growth.
Maintenance
Feed the roots: start with 2–3 root tabs at planting and add tabs monthly, increasing the amount as the plant grows. Remove old or fading leaves at the base, especially the emersed leaves that die back after the plant transitions to submersed growth.
Common Challenges
- Leaf melt after planting: emersed leaves fade as new submersed leaves form — this transition is normal.
- Stunting or pale leaves: usually a starved substrate; add root tabs.
- Slow plantlet production: opacus is slow-growing and rarely flowers, so division is often the faster route.