Both alveopora and goniopora are referrred to as "flower pot corals". Goniopora has a dismal survival rate in the home aquarium. Alveopora only slightly better.
You can tell them apart by counting the little fingers on each polyp..alveopora has 12 or under and goniopora more like 20 plus.
If I were you, I would consider taking the coral back to the store.
This is taken from wetwebmedia
Can you please take a look at the attached picture of my new tankmate.
<thanks kindly. It is clearly a Goniopora species. Very difficult if possible for any beginner to keep. Actually, its extremely difficult for advanced aquarists to keep too. Most die within weeks of import. This one will almost certainly not live to see a year captive at any rate unless you make rapid changes in system design or get it to someone that has a better shot at keeping it. Shame on your dealer for selling it to you without advising you of its needs, and quite frankly bud... you need to shoulder the same blame for buying a living creature without knowing its needs and if you could meet them first. It will likely cost this animal its life>
I am trying to identify him and to get more info on habits, lighting, feeding, etc. to keep him happy.
<please use the genus name "Goniopora" to do a keyword search in our wetwebmedia.com archives (use the Google search tool on the home page). There are many FAQs regarding this creature. I will also say that the animal CAN indeed be kept... but not likely the way you want to keep it. It needs deep sand bed systems (perhaps 6" plus) that are mature and have been established for some time to generate natural plankton. Seagrasses kept in-line in a fishless refugium may also be extremely helpful for producing phyto and epiphytic matter. It will benefit by being kept on the sand bottom in a colony with others of its kind... but will likely suffer in time in a mixed "reef aquarium" packed with a variety of species conducting silent chemical warfare on each other (allelopathy). You are going to learn a hard lesson on this coral most likely and I do hope that you will be sure to not only research an animals need before you bring it home... but also be sure to quarantine it. Again, please browse our archives where there are many thousands of pages that should interest you (like QT articles by Fellman). Be mindful too of infection with this coral. The brown jelly infection that commonly afflicts Goniopora as they begin to die can wipe out many/any of your other healthy corals in the display>
As for why it isnt opening, what was your acclimation procedure? If it was acclimated properly and is in an area that has the recommended amount of lighting and flow, it may just take a few days.