Mr. Saltwater Tank

Terrible Advice Tuesdays (T.A.Tues): Coral + Bleaching = Dead


Terrible Advice Tuesdays (T.A.Tues): A coral that has turned white is dead and should be removed from your tank.

The rest of the story: First things first. A coral that has turned white (called bleaching) is not a good thing. The bleaching is a sign of stress and stressing your corals is bad.

And, just because a coral is white, that doesn’t mean you should immediately consider it dead. Corals can bleach out and sometimes recover. That being said, how do you know if the white coral is dead or not?

For soft and LPS corals the answer is easy: as long as there is still flesh or a single polyp alive, the coral isn’t dead. Take for example zoanthids. As long as there is still a polyp visible (even if it is closed up), the coral is still alive.

My gold torch coral once it recovered
For LPS coral, if there is any flesh on the coral, the coral isn’t dead – at least not yet. A LPS coral that is losing flesh and exposing its white skeleton is not happy. It might dying off and it might just be damaged. I’ve seen LPS corals completely bleach out, yet still retain their flesh and recover to become beautiful corals once more. A great example is my aussie gold torch coral (see picture at the right) that bleached out completely and I was able to recover it back to its original golden yellow sheen as shown in the photo.

For SPS corals, if you can see any polyps on the coral, then the coral is at least still alive and may recover. A SPS coral that is white and doesn’t have any polyps is dead in my book.

When it doubt, leave the coral in your tank for a week. If the white part of a stony coral turns grey and algae takes over, consider the coral a goner. For soft corals, if all the flesh of the coral is gone, not surprise here…it is dead. Remember: white coral = not a happy coral, but not necessarily a dead one.

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Comments for this article (8)

  • kevin says:

    For sps, sometimes a small patch of coral stays alive after problems. Even a small patch of flesh is enough to grow an entire coral. So make sure the coral is completely dead. Also for SPS, i’ve made some errors, and lost some sps allong the way, however i still have some dead looking branches in the tank because at the base there is a small patch of polyps alive.

  • Andrew says:

    Hey Mark,
    How true is this advice oh wise one. I have a Branching Hammer Coral that I thought was long gone. I spoke to my LFS guy….another person I consider the most nobelist of fish gods. He told me not to give up on it, if it still has a GI Tract, feed it and it will in all likeleyhood come back. Well 6 months later it is thriving nicely, with at this time 6 large, thick, healthy branches. In fact it is bigger than my pajama cardinal. Anybody who wants to see a prime example of what Mark is talking about. ,notify me and i will gladly
    Display a fine example my Branching Hammer demonstraighting this topic
    Reef on fellow reefer….andrew….mardman1@ hotmail.com

    Reef on my fellow junkies……..,Andrew………..,mardaman1@ hotmail,com

  • Darren says:

    But at what point do you get tired of looking at half dead coral. More importantly at what point does a sick or dying coral start to foul the water. There was an interesting article in advanced aquarist about how dying corals affect young corals.

  • what damage control tactics should be implemented.eg.lower lite intensity,h2o parameters.major additives eg.strontium,essential elements,feeding,h2o temp n h2o change.anything else you can suggest?

  • my montis are bleaching at certain areas especially green.on my 3rd week of researching.help !

  • Darren…you can always frag off the dead/dying parts of corals that are fraggable.

  • John Vandersloot says:

    This is one of the reasons i set up my sump with a frag grow out area. I toss them in there and do not remove for several months. I have had things come back which I was positive where gone.. With a small chamber in the sump, spot feeding is also easier. not a big fan of feeding corals but if they need a little charity once in a while who am I to argue. My skimmer is in the second chamber in the sump and probally helps minimize any negative effects of spot feeding….never had a algea problem.

  • Rob C says:

    In my experience most coral turn white from high placement in the tank and overexposure to high intense light. When the animal turns white you basically kill the photosynthetic algae that is inside the coral which has a symbiotic relationship with the Coral to feed it and keep it healthy and to give a color. I have had much success moving the coral to the bottom of the tank and in a shaded area away from predators and intensify light. I feed it directly at dusk with helpings of Zooxanthellae till Color starts to return back and then I slowly move it up to the top of the tank. This has worked many times for me and I learn my lesson to start the coral at the bottom of the tank when I first introduced them into the system after the quarantine period has ended.

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