stream bogmoss

Mayaca fluviatilis looks at first glance like a moss that forgot how to stay small. Its thin, soft, pale-green stems are densely covered with tiny narrow leaves, and under good light it grows at a speed that catches most aquarists off guard. It is a true soft-water plant, and its care is easiest in water that matches its native streams.

The stems branch readily; replant healthy cuttings after trimming. The plant prefers soft, slightly acidic water, with carbonate hardness below 6 °dKH and a pH of 4.5 to 7; it can be kept in harder water too, though it usually grows less vigorously there. High light and CO₂ in the range of 25 to 40 mg per litre are both needed to keep the growth dense and the lower stems from going bare.

The recommended temperature band of 23 to 25 °C is narrow, and the plant is not hardy outdoors. It comes from tropical and subtropical America, where it grows in slow, soft-water streams. Given warm, soft, acidic conditions and strong light it forms a bright, airy clump that works as a background or midground filler unlike any conventional stem plant.