I posted this same question a few weeks ago. I was told to try picking shrooms from the wild and replanting them in my tank. Hopefully the spores will be spread throughout the tank and then little shrooms will pop up. I havent had any luck yet, but I do have the occasional small white mushroom pop out of my moss. I picked my moss from the woods where I know no pesticides have been sprayed and I guess theres spores in the moss.........Good luck to ya!...........Sara