Ottelia japonica

Ottelia japonica is a rare species endemic to Japan and parts of East Asia, found in ponds and slow rivers with clear, warm water. Its submerged leaves are unusually narrow and strap-like compared to the broad-leaved O. alismoides, with gently wavy margins and a fresh, translucent green colour that gives the plant a clean, elegant appearance. It is among the more demanding aquarium plants, requiring consistent CO2 injection, bright light, and soft to moderately hard water for sustained healthy growth. Despite these requirements it is considerably smaller and more suitable for medium tanks than other Ottelia species, and its rarity makes it a prized addition for planted aquarium collectors.