Did that kill off your coral thefishgirl or was it dead already? If so how long did it take to do the damage?
My sponge is Jet Black but has not caused a problem....yet:embarrased:
I noticed this sponge on this coral several months ago, but only in the last 8-12 weeks did it really start stretching around the rock. I've included a pic of this echinata when it was alive. It has only recently really started going down hill. I've been traveling a ton, so not a lot of time to dedicate to this tank unfortunately.
Now that I've seen this picture... this loss just makes me sick!!!!
I totally agree with removing problematic species from a reef tank. However, from your description it doesn't sound like there's any problem.
I think getting some ID on these sponges is the next logical step. "Invertebrates: A quick reference guide: by Sprung has a whole chapter on sponge ID. I flipped through it and the only sponges listed in the book as potentially "harmful to corals" are Chrondrilla aka chicken liver sponge (brown, black, gray or dull orange) and Collospongia aka ear sponge (blue, gray or purple). Based on your description I'd venture to guess you have Clathrina aka leather latticework sponge... a harmless hitchhiker. Try a Google image search to see if any of these genus match.
I have a bunch of encrusting sponges, so far so good but I also have a "Newer" black sponge like the one TFG describes. It has not chocked anything out yet but I am keeping a close eye on them just to make sure.
I think that if I have to kill it off I will us a Kalk slurry and apply it with a syringe. I have had a lot of success with doing this to fight off Aptasia.