Help with ID: What is it?
 

Hi all,

Just starting up a tank and received some live rock. I noticed that it has this white stuff on one of the rocks. Is it a sponge? fungus? Is it dead? Should I remove it?

It is outlined in red in the pictures below (one with, one without the flash).

Thanks in advance.

http://members.shaw.ca/nemod/aquarium/id01.jpg

http://members.shaw.ca/nemod/aquarium/id02.jpg

It is really out of focus, but even so, my guess would be sponge, and I would not worry about it.:mrgreen:

It's sponge, might turn blueish. I had a nice yellow one grow outa nowhere, something ate it.

Ok, thanks.

But aren't sponges not to be removed out of water? When I was transporting this rock, I'm sure it was out of water several times. Shouldn't it be dead because of that? What color does dead sponges turn to?

Some sponges are more resilient than others.