Here I describe evidence that an undescribed species of Arcobacter present in a small fraction of aquariums is responsible for the Brown Jelly Disease of corals, and can be treated with an in-tank antibiotic treatment.

To avoid duplication of content, and because the discussion that follows is likely to be at least as useful as the post itself, I direct the reader there:

Experimenting with in-tank antibiotic treatments for Brown Jelly Disease