It is H. crispa. Most H. crispa have purple tips on their tentacles, but once in a while you find them with yellow tips.
Your's is a little bleached, so you will need to feed it meaty foods like shrimp, scallops or silversides about 3 times a week until it regains its symbiotic algae. Then you can cut back to one or two times a week.
They need reef type lighting.
Some will bury their foot in the sand while others will put their foot into a crevice in the rocks. Where you have him gives him a choice. I doesn't look like it is attached yet. Hopefully that will happen soon.