I was interested as well, here is what Reeflady told me"There are many differences between different types of sponges & gorgonians.
Photosynthetic gorg's, as long as you provide adequate light and very good water flow, are relatively hardy.
Non-photosynthetic gorgonians require a lot of food, and are considerably harder to keep.
Sponges - many "hitchhiking" sponges do well in captivity. The more sought-after ones (blues, oranges, reds, yellows), can be more difficult to keep. The require a lot of food, and excellent water flow/circulation"
and here is what you told me when I asked the same question "read the new book from robert fenner called the natural reef invert ! great book with all ? answered "