Riccardia Chamedryfolia (Mini Pellia) is a very small liverwort that grows very slow and is a great plant for shrimp to pick through.
It will grow on wood or rough rock (epiphytically or lithophytically) if given the chance... at least until it gets thicker and the underside is too shadowed for the attached thallus to keep hold.
Size 1.5 inches x 3 inches on steel mesh
Very rarely seen!!