Over the past year I've noticed this sponge in the back of my tank, growing up arms kind of like cactus. I don't know where the sponge came from, perhaps it's from the DBTC for the Black Branching Sponge ( http://www.bareefers.org/home/node/7489). No matter where it came from it's pretty neat- it grows upwards like a tree, moves a bit in current and has blueish white tips, especially to the top branches. The body is very dark and looks black to me. It's middle to high in my tank right now so it can take light. I have to thrown in one of my favorite aspects of sponges- they're immune from LPS sweepers. If you want a piece, I can cut a few branches off and deliver at the frags swap in August. Standard DBTC rules and pick a # from 1-20. Edit: Be sure to read this thread before taking a piece so you are educated on it and any possible issues with it. If anyone is uncomfortable with it and doesn't want a piece, I'm not offended. 2 experpts to be aware of from this thread are: From Tuberider: One thing to note about this sponge, is that it either has a symbiotic relationship with gram positive bacteria or consumes it as it is one of the only things affected when I dose EM into tanks, keep that in mind. Not to say that we all use EM, I rarely do, however, from a propagation standpoint I feel obligated to share my experiences. From Gresham: Also note: some people are very allergic to this particular sponge. I know several that are and one that can not even put his hand in a tank where the colony has been messed with in any manor.