They can only be glued if you cut a small piece of rock from underneath and glue the rock. Mushrooms slime way too much to glue alone. I use a pair of wire cutters to cut some of the liverock underneath and the shroom comes off without damage. I saw a video where a guy used a pair of hemostats to peel the mushrooms off but you'd have to get them to attach to something solid or they just float around.