# Marine Aquariums > Corals questions and answers >  what is this?

## Nicky M

Attachment 174

I've had this thing in my tank for a few months and no one has been able to specifically identify it for me.

Its grown a bit since I took this photo, about the size of a 50p, and the knobbly bits are getting a bit longer. It moves about a bit over time, and is currently sat half way on the rock and partially on the sane. It does look like some weird kind of mushroom, but I want to know more about it.

I've asked on other forums but no one has come up with a concrete answer!

Hello BTW! I've not posted for yonks because its been so quiet then today I check and there are 59 unread posts!

Nicky

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## Timo

It looks like some sort of free-living mushroom hard coral. Try googling mushroom hard coral but i don't think there's much info about them.

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## Gary R

Its good to see you back with us Nicky  :Wink: 

Yes this looks like a young disc-shaped mushroom coral Which as tentacles on it that move it about, i think these come from the shores of Singapore if iam not mistaken.

i will do some digging and see if i can find anythink out on it for you

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## Nicky M

Thanks

I must have trawled through hundreds of images from the various suggestions I've had.

After googling free living hard mushroom corals, I found tons of images where the centre part matches, but I've yet to see one with nobbly tentacles like this.

The most like it that I found were from site relating to singapore though.  Isn't it odd how these things suddenly appear on a piece of rock I bought about a year ago. It came from world of water and had nothing at all growing on it, I only bought it because it was a nice shape

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