There is a lot of stuff in there that you can not see. As nice as critters are, a diverse microbial culture will be very hard to get without good live rock.
Saying no thanks to a very rich ecosystem because there might be an Aiptasia or something on a rock seems a little silly to me.
Saying no thanks to a very rich ecosystem because there might be an Aiptasia or something on a rock seems a little silly to me.