Sun shapes on gray shell?

[weagle117]

Can anyone tell me what these little sun shapes are? They almost look like prehistoric cave paintings They pop up in my tank on various objects- usually shells now that I think about it... They are hard... I asked at my fish store and no one knew what I was talking about. They always look just like this ... Thanks!

 

[Sharklover]

Looks like some sort of starfish

 

[weagle117]

It doesn't move & it is hard...

 

[Unicorn]

Can anyone tell me what these little sun shapes are? They almost look like prehistoric cave paintings

maybe ur fish are trying to tell you something LOL
Dear Hand that feeds us daily, please give us more live brine shrimp! Sincerely, your fishies ^.^

Sorry, I just couldn't let that sit in my head without letting it out.
It looks like starfish, but h said it's hard and doesn't move
I have no clue, to be honest and wanna know too. Hope somebody knows the answer

 

[weagle117]

Thanks for your comments.... does anyone have any other ideas???

 

[mr_X]

hydroids?

 

[weagle117]

uummmm??? maybe..... do I like that answer? They are hard feel like ridges on the shell.... at least the others did...I can't reach these without moving big rocks....