Hi Beth.
Well, SeaHorse_Fanatic is right about non-photosynthetic gorgs needing to stay clean from algae and needing to be fed. They need to be fed often. There are several non-photosynthetic gorgs such as the Red Gorgonian (Diodogorgia nodulifera) and the Pacific Acanthogorgia Sea Fan Gorgonians. From what I've read, the Red Gorgonians would be easier than the other one. People have had success with the red one and Reeftopia calls them hardy (easy) and suitable for reef aquariums.
http://www.reeftopia.com/Gorgoniansponges.html However, you will also find people calling them impossible to keep.
I have one of each. I wouldn't say that I've had success any of them yet. The Red Gorgonian that I have now has been in my tank for 6 months and the Blue one for 3 weeks.
The Red Gorgonian seems to be doing fine and I've fragged a piece for SonOfSkyline. I do move it around a lot trying to find the best place for it. From my observations, it will extend its polyps only when there is high waterflow. Without waterflow, it will not extend its polyps. I have seen it eat cyclopeeze, small brine shrimp, and crushed Ocean Nutrition flakes. I doubt it will eat phytoplankton. Because its polyps are semi-transparent, you can see the food go down the polyp and into the gorgonian. Its neat.
It is difficult to keep algae/detritus off the gorgonian though. I find myself needing to blow the algae/detritus off the branches w/ a turkey baster every few days because they have a hard time shedding it off themselves.
So I find that the coral needs very clean water and lots of food, which is quite a contradiction. I decided to try putting the coral below (but not directly below) a mechanical filter (w/ the prefilter installed). That helped a lot because now, only clean detritus-free water pours down on it keeping the gorg very clean. When it is feeding time, I turn off the filter so food doesn't get trapped in the filter. Anyhow, I'll see how this goes.
The Pacific blue gorgonian so far is doing well. Its polyps are fully extended during the day and it is placed at the end of the tank where all the food will eventually find its way since it is on the opposite side of the powerhead. It is too early to tell how well it will do. Its not a common coral and from most accounts, most people can't keep it very long.
You will have to do a lot of observing and feeding and adjusting if you want to keep them. They aren't easy for sure.
