Non photosynthetic Gorgonians are extremely hard to keep. In order to "feed" the enough you almost have to compromise water quality.
Quote:
"Unlike other gorgonian species, the yellow gorgonian is not photosynthetic, instead using its polyps and tentacles to trap passing organisms for food. (Because of this fact, yellow gorgonians can be more difficult to maintain in an artificial environment, as they will need to be fed a diet of baby brine shrimp, marine snow, phytoplankton and other micro organisms at least three times a week.) The water flow should be moderately strong and constantly flowing so that the accumulated debris on the outside of the yellow gorgonian will be washed off frequently, so algae do not develop among the colony. Even though the yellow gorgonian isn’t photosynthetic, it still needs access to some light to thrive- it should be placed near the top of the tank if the aquarium’s lighting system isn’t ideal."
Most people I have read about online have not been able to keep these critters longer than about 6 months. First indication of death is that the polyps do not come out.
Do some more research on it. Hope yours fares better than others.