Clear-ish, brown-ish, little disk shaped mushroom thing

[grav]

This is the 1st time I've ever taken a snap of my thumb... on purpose.

Okay, so what is this? It came on a rock and I've had it for months. The Zoos on the same rock seem to go nowhere near it. Now it seems to be multiplying. Not sure if it is good, bad, or what. How big does it get?

Thanks!!

 

[John_Brandt]

When you touch it does it feel like it has a hard skeleton inside like a coral?

 

[grav]

No, not at all.

Touching it causes it to deflate and withdraw. Turns to 1/4 it's size.

 

[John_Brandt]

Shoot! I don't know what that thing is. It must be a Cnidarian, but what kind?

OK, now I'm going to ask you to gently feel right at the center. Is there a tiny disc-shaped skeleton in there?

 

[grav]

You know your stuff.

Yes, the center has a hard feel to it, disk, even cone shaped shaped.

So what then is a Cnidarian? A good thing?

 

[fishfanatic2]

'Cnidarian' is the term applied to pretty much all the sessile invertebrates, like corals and other reef-building organisms. What you most likely have is a Corrallimorph (something like that, these names are impossiblye to spell), which are the mushrooms and all that. So what you have there is 90% a mushroom of some sort, IMO. Hope this helps!

 

[grav]

Thanks much.

So, nothing to worry about huh? I like the look of the thing, and it is getting bigger and multiplying.

 

[fishfanatic2]

Nothing to worry about.

 

[John_Brandt]

grav, can you take some more pictures?

This is bothering me because now it seems to be a stony coral (you felt the skeleton) and I want to try to identify it. It has the look of a Scolymia or Cynarina, but then not.

 

[Anonymous]

Cnidarians include Anthozoans (corals, anemones) Scyphozoans (jellyfish) and Hydrozoans (hydra, hydroids) if I remember Bio class correctly.

 

[grav]

Here is a slightly better pic. You can see one of the little guys on the left, there is another in back.

 

[tld]

It looks like Scolymia to me. Just curiuos: John, what characteristic makes you think it's not?

Teresa

 

[John_Brandt]

It looks very much like Scolymia. But it is so tiny and reproducing at that size as well.

I'm not saying that it isn't Scolymia, I'm just hesitant about these things unless I'm comfortably confident