Correctly I.D.ing corallimorphs is a difficult task even for experts(looking for the number and type of nematocysts and distribution of surface and marginal tentacles). As aquarists we usually rely on visual reference alone. Rhodactis are typically described as having hairy vesicles, Discosoma generally have lumpy vesicles. It definitely seems to fall into the Discosoma genus based on this photo.

re what i think
 

i think it would look better in my tank,lol.