Yup...I'd agree it sure looks like a
Sinularia sp. ...looks like a healthy one too. Give your addition some time to settle and you should end up with a very nice coral.
Mine seems to like a moderate current and moderate lighting(but they do adapt well to a broad range of light sources).
Folks say they can release chemicals that may pose problems especially for SPS type corals. Mine has never been much of a problem towards its neighbors(not that I've seen anyway!)
Best of luck with yours...
Kip...yours look sweet...very nice pic!!