This video shows one of the many beautiful contrasts of color that this genus possesses. All Dendronephthya species are aposymbiotic, being voracious feeders, absorbing many nutrients in the water, as well as feeding on phytoplankton and/or zooplankton with their polyps, depending on the species. They will also use sweeper tentacles to capture food in the wild. Carnation Corals are difficult to keep, with only advanced aquarists being qualified to own them. Going from the dealer to tank, they often deflate, never to return, then start to decay. They need a constant current and a constant drip of zooplankton and/or phytoplankton to keep them healthy, which in turn can pollute the aquarium.
The Carnation Coral is very difficult to care for and should be left to the experts. Although they are extremely attractive, Carnation Corals have a poor history of survival. Oddly, they have been known to change color! Unlike other corals, they do not use light and they depend on copious amounts of zooplankton and phytoplankton to keep alive. This can quickly pollute a captive system. One suggestion is to hang them upside down, as this is a natural position for them. Strong water movement, perfect water quality and a constant drip of phytoplankton is helpful.
The Dead Man's Finger Coral, Alcyonium digitatum is one of several temperate or cold water species must be provided with a cool water environment, which will mean having a chiller for the reef aquarium system. They need 50˚ to 69.8˚F (15 to 22.2˚C), so in a normal tropical reef tank, it will die in that environment in about 2 weeks. Provide a tank that is at least 29 gallons and they can be fed Marine Snow and similar products. They encrust and grow to 10" in height, forming 1" diameter "fingers" and are cream, white or yellow with white to clear polyps and need to be fed several times per day. No to low light and strong water movement is best.
The Kenya Tree Coral can be easy to moderate to care for. They come from a more nutrient rich environment and they are more dependent on outside food for survival. They depend on foods in the water column like phytoplankton more so than light. This coral does not need to be under Metal Halides, but they still need good turbulent water flow. Do not expose to fresh water when topping of your tank. This stresses the coral and may lead to its eventual demise.
The Red Dead Men's Finger Coral is different from the Dead Men's Finger Coral (A. digitatum) in that it has much shorter "fingers" and prefers a soft substrate and slower moving water. The Dead Men's Finger Coral, A. digitatum is reddish during the period of inactive spawning with the redness caused by algae and hydroids. The Red Dead Men's Finger Coral, A glomeratum is red all the time and has white polyps. Same cold water care and multiple feedings per day.
As referenced in this paper, the X. elongata has beautiful contrasting polyps and tentacles. They are one of the more sought after because of this. Check your new Xenia for Xenid craps which will come out at night and look JUST like the polyps that they sit on top of and eat!