unknown growth on LR

[EBR]

Hey Everyone --

There have been some patches of this thick covering on the LR ever since I got it almost a year ago. I upgraded my lights from 50/50 to PC about a month ago, and it seems that the stuff is spreading. I always assumed it was a feature of the particular rock that had it, but since it's growing, I suppose it's some sort of algea or other critter. The patch of it in the picture did not exist 3 weeks ago.

Any thoughts?
Thanks.
Matt

PS -- It's amazing what comes out when you upgrade the lights -- it's like getting the new rock all over again

 

[Fluff]

I'm not sure. Is it leathery? Does it have any openings like a sponge? or polyps?

 

[Brad]

I have patches of this on my LR. It doesn't spread much at all, for me. I suspect is some kind of soft coral or sponge. Don't expect it to get any more interesting...that's all it will ever look like!

 

[xxmoorishmanxx]

ditto

 

[electrikat]

I have several of those on one of my polyp rocks. Mine are yellow but look just like that. I think they are a sponge, but have had them in and out of the tank several times and they have not gone away. I had heard that sponges have to stay submerged and not exposed to air, so I don't know.

 

[Ducky]

Looks like a sponge to me.I have a few in one of my tanks as well and they have not gotten much bigger than the one you are showing and they have been in the tank for about 3 years.

 

[EBR]

Great! -- many thanks for the help.
Matt