My medium sized rock is covered in mushrooms. They cover each other all the time and never move. As malkore said they will relocate if the lighting isn't right. They will definately relocate if they have flow on them. A little flow is fine.
Just pick up the lost mushroom and stick him in a crevice of some LR
. If they like it there, they may attach in a day, but sometimes it takes 2 weeks.
29gal BB | 42+ lbs LR
| 143watts PC
| Asst. Leathers, Frogspawn, Hammer, XLG Open Brain, Zoanthids, Mushrooms, Diploastrea heliopora | Blue Mandarin | Atrosalarias Fuscus | Pair Captive Bred Ocellaris Clowns | Peppermint Shrimp | 6 Astrea's |