I'm new and need help identifying this (fuzzy green/yellow stuff)

[angela1]

Please forgive me if these are common (I'm new).

I bought established live rock from a 4 year old reef tank and this yellow/green fuzzy kind of web-like growth is all over one of my rocks. I was told by someone local that they thought it was a 'yellow mushroom' but it doesn't look like a traditional round mushroom at all. It's beautiful but I have no idea what it is!

a large round maroon colored mushroom appeared on it (seemingly out of nowhere) this last week.

Thanks!

http://reefcentral.com/gallery/data/500/219833Soft_green_mushroom_fungus.jpg

http://reefcentral.com/gallery/data/500/219833soft_green_mushroom_fungus_2.jpg

[KarlBob]

That would be a sponge. It won't hurt anything. It's a filter-feeder that will help to keep your water clean, and it looks pretty. Congrats on the nice hitchhiker.

The maroon mushroom may have been somewhere else in your tank, possibly on the underside of a piece of live rock. When they aren't happy with their position, mushrooms can let go, drift in the current until they land in a place that suits them better, then grab on to the new rock.

[angela1]

A sponge! How awesome is that for a surprise :)

Any chance anyone knows what kind of sponge? I'm coming up empty handed in my searches .... might need to get a good book.

Thanks for your reply!

[KarlBob]

You're welcome.

Sponge IDs are more difficult than coral IDs. Someone in a well-stocked marine biology lab would have to analyze its spicules, the tiny crystalline bits that give the sponge its shape and structure. If you can find it in a book, please let us know what it appears to be.

Here (http://reefkeeping.com/issues/2005-07/rs/index.php) is a link to an article by Dr. Ron Shimek on the difficulty of identifying reef aquarium sponges.

[angela1]

Thanks. Unfortunately all of my rock was exposed to air when it was brought to my aquarium....the sponge is starting to look white under certain lights and I'm guessing thats a sign that it's dying.

Bummer :(

[KarlBob]

Maybe, maybe not. Some sponges just like concealed, quiet spaces, and shrivel when they're exposed to current and light. If you move your rocks a year from now, you might find a new crop of the same sponge has grown underneath and between the live rock.

Some sponges can survive encounters with air, and some can't. I think it's just a waiting game, now, to see what will survive and what won't.