Sometimes it is hard to tell when a coral is starting to get sick.
Not only do they not have eyes (or legs, or arms, or....), they have only two thin layers of skin (outer and inner) and not much else. So when they do get sick, it is not always easy to tell.
I have never heard of a coral getting a "cold sore," but I have heard of corals getting bacterial infections. So that little spot makes me nervous. I will have to keep an eye on it. Like any healthy animal it will most likely beat the problem on its own and look better in a day or two.
But it is not always so, disease outbreaks in corals can be catastrophic. The Florida Keys are good example. Over 90 percent of their magnificent staghorn coral is gone - largely through disease - nor are their other coral's immune (check out NOAA's coral disease page for more info).
So what can we do? Well, we can keep an eye on things (after all, we are the ones with eyes). Check out Dr. Greta Aeby's "Eyes of the Reef" site. You can even go to one of their trainings and become a coral disease expert.
It is also important to support the scientists that are studying the diseases. They are finally moving past the initial stage of just identifying diseases to thinking about ways to control or reverse disease outbreaks. For instance, if a coral has a tumor-like disease, what happens if we simply cut the bad tissue out? Will that be enough for the coral to heal up? Seems simple, but we don't know if we don't try it.
Our scientists are starting to do things like this. They are figuring out the diseases, looking for how they transmit, and then being creative in solving them (CDC Hawaii reef style).
So maybe we have a chance that other areas did not. Here's to healthy corals and healthy reefs!