ID - What lives in this????

[Jenn]

I have 2 of these growing in my tank (that I can find) and would like to know what it is or lives in it?

Thanks,
Jenn

[Ram_Puppy]

are we looking at the bluish object center frame?

can you give us a little description? it kind of looks sponge like.

[GaryP]

Jenn,

Are you referring to the hole? If so it was probably made by some sort of burrowing shrimp like a pistol. DO you have a pistol shrimp? Its pretty hard to ignore them.
I'm assuming its not a burrowing goby because you would probably see it coming in and out of the hole. Some pistols are primarily nocturnal.

Gary

[Jenn]

I'm referring to the gray sponge-looking thing in the middle of the pic. I went to touch it and it feels fleshy - not hard, but not soft and spongy either. It appears that there are some type of trails made in it or something.
I don't have a pistol shrimp, and my firefish has a burrow down a little from this.

[Viet-Tin]

Do the holes ever close when you touch them? If so then thy might be some type of tunicates

[scuba_steveo]

I have the exact same thing but I have no clue as to what it is.

[alexwolf]

Its a type of sponge. I got some on a rock of blue zoos, at least thats what the vendor told me.

[Jenn]

The holes stay open as I touch it. Its just weird that nothing picks at this like the other sponges in the tank.
Thanks guys. At least I know there are others too.

Jenn