Echinodorus subulatus (Narrow Leaf Sword) is a hardy, popular aquarium plant known for its long, spear-shaped, strap-like green leaves that sway in the current, forming a lush background or midground element in aquascapes, especially for beginners, as it's adaptable and tolerates low-tech setups but can grow tall (20-45 cm). It spreads via runners and thrives in bright light but requires good substrate and benefits from CO2, with new leaves sometimes showing bronze hues.