I don't know if riverwonders.com is reliable. I bought some live rock. First, they arrived dry in used cardboard boxes in the cold weather. I guess all live rock has become dead. Second, it took quite a while and I called and sent emails but no reply. The rock did, however, arrive. Third, it seems that they are just rubbles bound together by some cement. Very little coraline. Fourth, I was surprised that Tonga Rock was much heavier than Fiji, which did not make a lot of sense. Fifth, I sent them email and they claimed that the rock was natural but no longer available (in the web, continue to advertise).