What is this, ID please.

[rach4194]

I got a couple of pieces of lr the other day and I was looking closely at this one and noticed it was opened. When you touch it, it closes up tight and moves a little.
Here is a close up picture, it's not as open as it was a while ago. I Will post another pic when it does. (If need be.)
Thanks for any info.
Rachel

 

[viper_930]

Maybe some kind of oyster?

 

[bigarn]

Scallop?

 

[bang guy]

It's a Yellow Thorny Oyster.

 

[ryand]

with clorafill on it weard

 

[chamic1]

I got something similar to that. It is stuck in the LR. It was a hitchhiker with some feather dusters. I noticed that it opens and closes too but it seem to be attatched to the rock. It is about 1 cm long and it has coraline algae on it. I'll try and post a pic of it.

 

[ashenwolf]

I have three of these in my tank and they seem to do no harm. If it is an oyster, its a filter feeder so it would probably only help and not hinder the tank. Two are attached to one peice of LR and the third is by itself, though looked like a rock when i first got it. Hehe, the strange things you find

 

[rach4194]

Here is a full pic of the rock. The first pic is the bottom of the rock, in this pic it is the same on top, it opens and closes. Is this even a rock at all? The yellow sponge was also attached to it.

 

[rach4194]

Here is a one more, of course it's all closed up now. It's really strange.