Dave,
I am not sure if I have Caribbean rock. These have appeared in the last three weeks and are very prolific. I saw one then discovered half a dozen. The interesting thing to me is that the last thing I added to the tank was a brain frag I got at our frag meeting. That was months ago - and now these are appearing?
When I first put in my live rock I was too new to 1) ask where it came from and 2) weigh it. I never thought any one would ask. Next tank, I will know these things.
sara