Brain Coral Skeletal Question

[Monte0101]

I have both an Open Brain and a Closed Brain member in my tank. The Open Brain appears to have a coral skeletal base, while the Closed Brain appears to be growing on a simple rock. My question is this. Are their bases made up of coral skeletal matter, or are they growing on rocks? The reason that I ask is because I am wondering if they will always remain the sizes that they are, or will they grow in mass?

Thank you!

[Gary Majchrzak]

both skeletons will increase in mass as they grow.
To give a more specific answer it would greatly help if we knew the specific coral species that you're referring to.

[Monte0101]

After looking the names of them up, perhaps they are both closed Brains. My Wellsophy appears to have a skeletal base, while the Favites appears to be growing on a rock. So are you saying that what appears to be a rock is in fact skeletal growth that will continue to grow in size?

[Gary Majchrzak]

Experts correct me if I'm wrong, but the larvae of Wellsophylia settle out on the substrate and grow an unattached skeleton.
Favites larvae will settle out on a hard substrate (like a rock), encrust and grow outward from there. As they grow larger, Favites might entirely cloak the substrate that they first settled out on.

[Monte0101]

That makes sence. The bottom of the Favites looks just like a rock. That being said, it will never enlarge past it's existing diameter, correct?

[Gary Majchrzak]

<a href=showthread.php?s=&postid=10111319#post10111319 target=_blank>Originally posted</a> by Monte0101
That makes sence. The bottom of the Favites looks just like a rock. That being said, it will never enlarge past it's existing diameter, correct?
Favites can grow over the entire rock so that you can no longer see the rock.

[seapug]

The wellsophyllia is a single large free living polyp with a skeletal base. The Favias are colonies of many individual polyps that spread on substrate like Zoas, but each one has its own skeleton and can live if the others in the colony die.

[Monte0101]

My thanks to each of you for information.