Goniopora is a "death coral". Their succes rate is pitiful. Please don't buy them as it only causes more to be harvested.
You will need to feed it tiny meaty foods like cyclops or rotifers. Thaw a bit out and suck it up in a turkey baster or syringe. You'll need to squirt the coral every othre day with food. Preferably with the currents in the tank shut off. When you see each "mouth" close up into a ball you know that they are all fed. Like Sun corals, they don't do well catching their own food. the only ones I've seen thrive were in a friends tank that was so nasty and full of algae you couldn't see in the tank. The excess nutrients were helping keep the coral alive. Found a lot in freshwater estuaries, where rivers dump into the ocean. These areas are always high in nutrients from runoffs. This coupled with the fact they tend to be in low water means they like high lighting and high nutrient water. The problem with us reef keepers is that our other corals will die in high nutrient conditions so the use of skimmers, reactors, water changes, etc... work against those corals.