Experienced Reefer
Please help in identifying the gelatinous ooze below. I first noticed it on my montipora plate I accientally "burned" by allowing a few drops of prepared concentrated plankton to settle on it at night when the water flow was lower. I thought it was just a dead spot that would grow back in time. This glelatinous "stuff" showed up on the dead spot instead of healthy tissue and since can be found on the rock and mostly one other susceptable acropora species. It seems to kill off the unbderlying tissue. it can generally be removed easily with suction during water changes but always reappears, especially on the montipora. Over time the original spot has grown much bigger. What should I do to ultimately rid this "stuff" from my tank. At this point, I am open to removing the montipora and the other acropora even though they otherwise exhibit normal growth.

The gelatin is whiteish tan and generally slimey. In time, it becomes more substantial and forceps may be used to help remove it. It locates on the rock and some SPS. It does not appear to affect LPS, zoos, mushrooms, or polyps though it may be near them.


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Need a closer picture but my guess from your description would be Didemnum sp., a very fast growing encrusting colonial tunicate. It can overtake your tank.

David Mohr


Sounds (looks?) right to me... - In my experience though they didn't overrun anything live, just colonized any "empty" real estate. They also seemed to diminish to a much more reasonable rate of population over time as well.

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