It should take a day or two to fully extend but if your water and lighting conditions are way different than where you got it, it could take a couple of days longer. Green Star Polyps are one of the hartiest soft corals I know of and a great starter coral. When we got ours it was the size of a dime and now it's aboout 12" across and would be much bigger but I frag it to keep it from taking over the tank.:yes: