the gargonia you have looks like a sea plum or purple gorgonia. they are photosynthetic but do need the occasional spot feed. this animal should not starve in your tank. they also have a calcium base and need to be treated like any other lps or sps coral.
The Purple Brush Gorgonian is also referred to as Purple Bush, Lamarck's Gorgonian, Feather Gorgonian, or Rough Sea Plume. It is a branching coral that is closely related to hard corals. It is pinnately branched, forming tall, feather-like colonies and has a beatiful purple coloration. The polyps are nocturnal, and the branches are bumpy in appearance when the polyps are withdrawn.
It is semi-aggressive and should be given adequate space away from neighboring corals or anemones. Underwater epoxy is commonly used to anchor its base to a piece of live rock in the reef aquarium. It is moderately difficult to maintain, but makes a rewarding addition to the well-established reef system. It requires medium to high lighting.
In order to inhibit algae and cyanobacteria growth, it is important that this gorgonian is provided with a medium to strong, constant or intermittent water flow. If in the event that it does begin to become covered with algae or cyanobacteria, remove it from the coral immediately, as this will cause rapid tissue deterioration. Algae can be removed gently with the use of a soft brush, and cyanobacteria can be combated by soaking the coral in freshwater of the same temperature for approximately 1 minute. These corals will also benefit from the addition of iodine, calcium, strontium, and other trace elements to the water.
The Purple Tree Gorgonian should be fed a few times a week with a filter feeding food. Provide a varied diet of live or frozen baby brine shrimp, Marine Snow, PhytoPlan and other suitable micro foods.