[Delphinus]

I have to back up Bob on this one. Elastics used to secure some frags, espescially softer liquid filled (for lack of a better term) corals such as mushrooms and colts, can sometimes just cut through the frag leaving you with two or more smaller (and unattached) frags. Colt frags in particular are notorious for not cooperating when you want them to attach to something. Some people suggest (I have never tried this myself) that "sewing" the frag onto a rock with nylon, cotton, or fishing line might help. Either the frag simply grows over the thread, or if you use something like cotton it will eventually disintegrate. But like I said I have never tried this myself, so take such advice with the appropriate sized grain of salt (or whatever your favourite condiment may be -- perhaps some cayenne pepper might be nice?)