I have some of those, they are the first "coral" I bought. They were sold as metallic green frilly mushrooms I think. I assumed they were yuma, but someone told me ricordia all split to reproduce, and regular mushrooms have will little babies break off of the stalk...these have smaller babies breaking off the stalk (you can see the smaller ones in your pic) so who knows. Whatever they are, they are really hardy. Lived through a bad crash when a huge leather died and polluted my tank, then survived for a few years after that when I let the tank go FOWLR with crappy lighting, and are still around, with a new lighting upgrade to keep them happy.