Cryptocoryne Parva

Scientific name: Cryptocoryne parva

Origin: Sri Lanka

Growth: slow, 3–6 cm

Light and CO2: medium light; no CO2 needed

Placement: foreground

Propagation: runners; divide clumps

Cryptocoryne Parva (Cryptocoryne parva) is the smallest of the Cryptocorynes, reaching only 3–6 cm tall with a rosette, the ring of leaves around a central crown, less than 5–8 cm wide. It comes from Sri Lanka and holds the same narrow, dark green leaf shape whatever the conditions, which is unusual for the group. Unlike most crypts it wants a bit more light, otherwise it loses its leaf shape underwater, but it still grows without added CO2, making it one of the few true foreground plants for a low-tech tank. It is also the slowest: a fresh pot will sit for weeks before it starts to move, and Tropica gives about six months for plants set a few centimetres apart to knit into a low group. Nursery leaves grown in air often melt after planting; leave the roots and new leaves follow. Do not let taller plants overshadow it. The tight low clumps trap food and biofilm, the microbial film shrimp graze, at shrimplet level.

Water: adaptable across hardness and pH; keep conditions stable, as sudden changes trigger crypt melt.

Planting: split the pot into small pieces and plant them a few centimetres apart with roots buried and the crown at the surface. It is a root feeder, so push a root tab (fertiliser capsule) into the substrate beside it. Leave it in place once planted.

Light and feeding: medium light, more than most crypts; shade makes it lose form. CO2 injection (carbon dioxide gas added to boost growth) is not needed. Feed with root tabs.