These are some Montipora cap. frags I pulled out of the main tank and have currently piled upside down for the photo.
Notice the one on the right. It has full polyp growth on the bottom of the plate.
You can see the rest of the frags have smooth, polyp-free bottoms.
I think this is called something like bi-facial growth vs uni-facial.
This plate was growing directly out into the return flow, so I guess it had such a consistent nutrient supply that it could sustain an army of polyps that weren't doing any light-gathering - just food gathering. Cool!
:-)
-Matt

