75 x 75 in mesh
This is a very easy plant to keep without much extra care, but like all plants, it can benefit from CO2 supplementation, although this is not required.  Like many mosses, it does not typically respond positively to most chemical plant supplements.  Many aquarists report success with this moss purely through keeping a well-maintained aquarium with no supplementation.
Quite often Xmas moss is mistaken for a widespread Java moss. Sure, at first glance they are very much alike.
But this is just the first impression you get. If you take a closer look, you will see the difference in the structure of its branches: