I have ongoing nightmares with Red Mushrooms growing out of control. Then there are your Mutant Ninja Purple Mushrooms, and some Brown Button Polyps. GSP's can be a problem. Among things that just grow fast are Colts, Sinularia dura, Devil's Hand, and Toadstools. I have also found Organpipe to be a bit weedy.

It seems that if you have smaller tanks a lot of pruning is necessary
