That looks like Diodogorgia nodulifera. They like lots and lots of linear flow. I have 4 of them, and the fastest growing one is 1/2" directly in front of my MP10, it is even growing towards the pump.
They are quite hardy IME. When they are healthy the polyps are huge and can eat frozen Cyclopeeze. If they have been starved the polyps will be smaller and you should start with rotifers, BBS, FM seafan, ultra min F, etc...