Quick Acropora Question!

[A_Lee]

I've had an Acropora sp. frag for some while now. It used to be in my 40g, but since about one month ago it has been in my 15H. In total, I've had the frag for about a year. The frag is not bleached or anything. Over the past year it has grown a tad bit. The tips are a whitish light blue color, so I take that as an indication of growth, slow as it is.
I am intrigued by this frag because, ever since I received it, it has never shown any polyp extension what-so-ever; not even terminal polyps! Is this normal for some species of Acropora?

 

[tuberider]

Some staghorns have very small polyps, I have the old ORA Indo blue tip stag and unless it is super happy and I happen to catch it at night you wouldn't know it has polyps. It's happy and grows like a weed, but no PE.

 

[A_Lee]

This one definitely has no polyp extension during the day time. I'll have to check a night time Jeremy, I never though about that.
And at least it still has it's color!
Thanks jeremy