ID this "growth" please

[nojinnyc]

What is this dark purple stuff covering the base of my coral?

 

[Dtech07]

Do you have a pictures??? there several things it could be.

 

[nojinnyc]

Sorry completely forgot to add pic

 

[Dtech07]

Minus the flash looks like dark purple coralline algae. Or a dark sponge hard to tell due to the flash but looking at the frag coralline.

 

[evolved]

It's an encrusting sponge. You may need to use a scalpel or a razor blade to scrape it away if it starts to encrust onto the coral tissue.

 

[Tab28]

A sponge would be my guess as well. There are several types that grow, usually in low light areas. Some will die if exposed to air or higher light levels. They are not bad unless in your case start to cover corals.