The mushrooms are the easiest to propagate, just cut of the head, place the head on a rock and cover with some bridal mesh and the head will reattach and where you made the cutting another head will grow. You can even cut the head in half and get more. Mushrooms are virtually impossible to kill and can grow like weeds. The same is true of the colt coral, remove the coral from the tank, use a sharp razor or scissors. Make a quick clean cut on a branch that has a few forks on it. Use super glue to attach the cutting to a piece of rock, you may also want to lightly wrap a rubber band or the bridal veil netting over it to hold it down. There's a lot of good info at http://www.garf.org
on propagating different types of corals, well worth reading. As to when to frag
, let the corals grow awhile and when they get too large for the tank or your tastes, trim them back.