They need all the live rock that fits into a 100 tank. They are extreemly picky eaters. They only like live pods that they pick off your rock. You need that big of a tank for your pod population to keep up. If not the mandarin will wipe out all the pods and then just starve after seeming like its doing fine for a month or two. A large fuge with some macro and live rock rubble helps your pod population too. They have been succesfully kept in smaller tanks but i would recommend that you don't try it unless your really know what your doing. In a 14gal tank it would be nearly impossible