Java Moss

Scientific name: Taxiphyllum barbieri

Origin: South-East Asia

Growth: medium, 3–10 cm deep

Light and CO2: low; no added CO2 needed

Placement: tie or wedge onto wood or rock; no substrate

Propagation: pull a clump apart and re-attach

Java Moss (Taxiphyllum barbieri) is the most forgiving moss in the hobby and the one most people start with. It comes from South-East Asia and is happy in almost any water and light. It has no true roots: instead it grips onto wood, rock or filter parts with tiny holdfasts, so it is never planted into gravel. Tie or wedge a thin layer against hardscape and within a few weeks it holds on by itself and starts to spread into a soft, irregular tangle 3–10 cm deep. Growth is medium paced, faster than the fancier mosses, and it copes with dim corners where nothing else grows. In a breeding tank it does two jobs at once. The tangle gives newly hatched shrimp and fish fry somewhere to hide, and it collects biofilm, the thin living film of bacteria and microscopic algae that shrimp graze on all day. Trim it with scissors when it gets thick; the loose bits will grow wherever they land.

Water: unfussy about hardness, pH and ordinary tropical temperatures. It tolerates gentle flow and still water alike.

Planting: spread a thin layer over wood or rock and hold it with cotton thread or a dab of aquarium-safe cyanoacrylate gel glue until it grips, which takes a few weeks. Avoid a thick wad; the inside shades out and browns.

Light and feeding: low light is enough and no added CO2 (carbon dioxide gas injected to speed plant growth) is needed. It takes its nutrients from the water, so a light dose of liquid fertiliser is all it asks. Trim regularly so the lower layer keeps its light.