Yes, mushrooms can and will release them selves and move. If there is too much flow or too much light, they will move. Mushrooms like lower light. I had one that moved from the top of a rock to the bottom every time I turned the rock over. They are hard to glue down so if one does release its self, set it in the sand in an area of very low flow. It will attach its self to some sand and you can then glue the sand to a rock in a low light, low flow area and it should stay there
