locally captured rock will be 'live rock', true or not?

[ShagMan]

Hey guys,

I'm going tonight to goof off at the local beach/pier/waterbreak (Dauphin Island, a barrier island off the coast of Alabama), and look for hermit crabs, maybe some small fish and I'm *thinking* I can get live rock as well; is any submerged rock considered 'live' as in what I would need for a reef tank or are there some special considerations? Thanks for helping a newbie.

 

[Anonymous]

Well, it would be considered live in that it would be host to beneficial organisms for your tank, but it would not function in terms of maintaining water quality unless it has tons of nooks and crannies like rock that originated at a reef. So if it looks like a heavy chunk of granite you could get some for the organisms but there would be no point in lugging home huge pieces- just buy some base rock instead. But if they are light weight with lots of holes it might be good- don't know what the rocks are like in your area...

 

[ShagMan]

Ahhh, I see... well the rock locally will probably be chunks of granite, so won't do me much good... I'll look around just in case though, I have seen porus volcanic rock in the area before.