Caribsea Aquascaping Prine Reef Rock 40 lbs The ultimate rock for marine, reef, or African Cichlid ecosystems. Packed with holes and textures, and incredibly porous, you can"t a better rock then this! They have great color as well, not too white, not too dark, and takes coralline algae growth beautifully. The freeforms lock together nicely for stability and because it"s natural rock each peice is unique. Product Features: . Ideal for marine, reef and African Cichlid aquariums . Loaded with holes and crannies