Fissidens miroshakii

Fissidens miroshakii is a rare, collector-grade aquarium moss originating from Japan, where it grows on submerged stones in cold, clear mountain streams. Its fronds are deeply pinnate — more finely divided than either F. fontanus or F. nobilis — producing a level of micro-textural detail that is exceptional even within the highly detailed Fissidens genus.

This species is among the most demanding mosses in the hobby. It requires cold, soft, very clean water with strong CO2 supplementation, and struggles in tanks above 22°C or with significant organic loading. For aquarists who can meet its requirements, however, the results are extraordinary — patches of F. miroshakii on smooth black stone are considered among the most beautiful moss displays achievable.

F. miroshakii grows very slowly and is expensive relative to other mosses, but its rarity and visual quality make it highly sought after for competition aquascapes and collector setups. It is best used sparingly as a featured accent rather than as broad-coverage moss.