Caribsea South Seas Base Rock is a stunning rock with high porosity, this rock is clean and safe for marine, reed and hard freshwater aquariums such as Africa cichlids. Its structure allows it to house huge colonies of bacteria for water filtration and hiding holes for your microfauna in reef tanks such as copepods, rotifers and amphipods. It also serves as a great surface for mounting corals. Combined with the Flat shelf, it will help you create a stunning AquaScape in any aquarium suitable for this rock. The picture is a representation of the rock. The rock you get will not be exactly as shown. They are natural and vary greatly piece to piece.