Please help ID something on my LR. Thank you for looking.

[Aquatic_Ape]

Hello RC. Thanks for taking the time to look at my post.

My tank has been running since 2011 and 3 weeks ago I found a small, membrane-ish growth the size of a nickel on a piece of LR. It is purple and blue and creamy colored and brownish maybe, and seems to have grown within the 3 weeks that I've noticed it into the size and shape of a loosely crumpled up piece of US paper currency (think dollar bill).

My own brain tells me that anything that grows this rapidly may be an infestation of some sort, or a generally unwanted companion to my reef tank. Maybe I am wrong. Here are some attached photos, and if anyone could more knowledgeably inform me as to what this growth is and more importantly if it is harmful or not, I would be very grateful. Thank you for your time and knowledge, Reef Central!

http://imagizer.imageshack.us/v2/640x480q90/845/3xiv.jpg

http://imagizer.imageshack.us/v2/640x480q90/837/fynw.jpg

http://imagizer.imageshack.us/v2/640x480q90/839/8qjb.jpg

I hope these images link.. :thumbsup:

[Aquatic_Ape]

I will resize them smaller, I apologize!

[gone fishin]

some sort of sponge maybe. Have you added anything new to the tank or has it just popped up?

[Aquatic_Ape]

I added a few peppermint shrimp from a very reputable LFS about 6 or 7 weeks ago, but nothing else.

I did redo my aquascape around the same time and it is possible this has been there since the beginning as an original hitchhiker, maybe it has just not been in a position to flourish until now. The rock it is on is in prime light and water flow area now..

Just brainstorming, thanks so much for interest in helping.

[cloak]

It looks like some type of macro algae IMO.

[Aquatic_Ape]

It looks like some type of macro algae IMO.

I am admittedly unsure as to if that is a good thing or a bad thing? In your opinion does it look like something that I should let go on its natural evolutionary path, or does it look like something I may want to remove from my tank?

[The Derelict]

I am not sure, but I would also guess sponge. You probably had it in the tank for a bit, growing in a more photo negative area before you moved your rocks.

[ReeferJohn408]

Sponge. I have some of those too.

[cloak]

I am admittedly unsure as to if that is a good thing or a bad thing? In your opinion does it look like something that I should let go on its natural evolutionary path, or does it look like something I may want to remove from my tank?

How does it feel to the touch? It should be fairly easy to distinguish between macro algae and a sponge.

[gone fishin]

How does it feel to the touch? It should be fairly easy to distinguish between macro algae and a sponge.

Good point. Nothing like a good mystery.

[Aquatic_Ape]

Haha oh I am going to lose major points here..

I haven't touched it yet. I use reef safe gloves when I put my hands in my tank so I can't speak to texture. Also, it seems paper thin and I am kind of a big guy and I have had a few cocktails tonight so I am not touching anything until tomorrow for sure.. :dance:

[gone fishin]

:lmao::beer:

[CoryD]

Hard to tell from the pic, but I'm also gonna guess a type of sponge. Also looks kinda like an aptasia toward the bottom of photo.