Take it and the ship out of the tank. Pull the moss out to make it a flat sheet or sheets. Get a spool of black cotton thread (cotton thread will eventually dissolve so be sure its 100% cotton not a poly/cotton blend like alot of thread is), start laying the moss on the ship in areas and tie, tie, tie, actually it will be wrap alot and tie. It will look bad at first but trust me the moss will grow, fill in, and cover the thread in time. I can't judge how much moss is actually there but as long as you can get alittle spread all over the areas you want and tied down it will eventually spread. One thing tho... is the finish on that ship smooth? If so the moss won't be able to grip. Plastic won't work, ceramic if the finish feels rough might actually work.