By some luck I discovered this moss in one of my tanks. It looked like mini fissidens ‘puffs’ thus I named it Fissidens ‘plume’. It is a mini variety with fronds 2-3mm in length. Grows quite compact. Very little maintenance required.
Fissidens Plume’ is not commercially available in South Africa and extremely rare in the hobby. Please be aware that you will only receive 8-10 Fronds attached to a wooden plate.