There isnt a real scientific way of telling you what it is without looking at it at the cellular level, they are usually just described in how they grow, so like a ball sponge or branching sponge.
They are filter feeders and will just take stuff from the water column and they dont like a ton of light. If he is doing well where he is, i would say that is pretty good. The ones we buy tend to be very hard to keep.