Sun coral not opening

Discussion in 'NPS Corals' started by nuisance, Dec 13, 2013.

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  1. nuisance

    nuisance Astrea Snail

    Aug 1, 2010
    Please advice. I bought a pinkish sun coral a few months ago (believe it must be a dendro). The polyps never want open and then I decided to put in the sump, not really attending to it. It is now some months later and the color of the coral is still the same. Do you think it can still be alive? Would the color change to white if it dies?

    Any feedback will be appreciated.
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  3. SaltyClown

    SaltyClown Sea Dragon

    Feb 21, 2011
    When sun corals die, their flesh comes off. Sounds like yours is still alive. I assume you know this. But sun corals need to be spot fed. Hard for you since yours don't open. Have you checked it at night? In the past, I've turned off the pumps and placed food on the closed polyp, to encourage It to come out. Sun corals should be fat.
  4. Greg@LionfishLair

    Greg@LionfishLair 3reef Sponsor

    Oct 17, 2011
    Coastal So. CA
    As mentioned, since it's azooxanthate, Tubastrea MUST be fed. They cannot live by the byproducts of photosynthesis. As to its condition, we'd need a photo.

    IME with this coral (we used to have several), they become accustomed to opening at a certain time (feeding time), altho once they get used to feeding, they will often open more and more when they sense your hand, or fish food in the tank.

    Most peeps use a bulb-type turkey baster to feed them, altho a 60 cc syringe with a length of airline on it and a length of rigid airline tubing an the business end of it is what we used. We even angled the tip of the rigid using a heat gun (be careful not to collapse the tube) to make it easier to reach the lower polyps.

    This photo shows something similar to what I mentioned, but it also has a "feeding cap" attached to the end to keep the food in proximity and the rigid tubing was bent on the tube-side to hang on the side of the tank...IIRC we were using it to feed phyto to our clams:


    Last edited: Dec 13, 2013
  5. Kevin_E

    Kevin_E Giant Squid

    Apr 30, 2009
    Mine rarely opens either. I've had it for 6+ months. I don't know how it's still alive.
  6. Va Reef

    Va Reef Giant Squid

    Jun 6, 2010
    Chesapeake, Va
    Aquarium Corals: A Look at the Sun Corals — Advanced Aquarist | Aquarist Magazine and Blog

    Interesting read on sun corals, seeing as Tubastrea only describes the genus and not the species.

    As far as yours in concerned, I'm not sure why you'd place it in the sump? however it was obviously getting some sort of nutrients down there.

    My feeding method goes as follows, and I find new heads popping up all the time:

    Coral frenzy around the closed/open polyps, turn off all pumps/water movers.

    20 minutes later the coral is usually all open, and I feed Mysis. If some heads are still not open, I baste some of the Mysis defrosting water onto the coral. I have found it opens up the most 30 minutes or so before lights off, thus making it the best time to feed.

    As others have stated, you may have to wait for an hour or two after lights off in order to do some initial feedings.

    My colony opens up every night with some polyps open all day too.