not terribly difficult, you can usually aim a powerhead at them and they'll let go of what they're attached to. You can also have a rubble field around the area that you have your shrooms so that way when they spread, if you don't want more, you can just pick up the rubble pieces that they're on and sell or trade them. As far as how fast they grow, just like any other coral, some grow fast and some grow slow that's why some are so outrageously priced while you can't give others away. I'll get some pictures up tomorrow, a word of caution, mushroom collecting can become addicting as there is just about every color and pattern that you can imagine out there.