it really depends on how long your tank has been established. Each time you introduce a new anything, you are increasing the bioload on your system. I truly feel that after you reach equilibrium between livestock and bioload, eachtime you try to add something new, something else will die. This is just a theory of mine anyway after some tragic stories. If you are just starting out, i would reccommend adding things slowly, until you can truly see the network of life develop in your tank. As your tank, and your knowledge as a hobbiest age, you will understand your tank better, and will be abble to tell if the anchor and frogspawn corals at the lfs will be ok to add. Good luck cause this darn hobby does require a lot of patience!
jon