is flat, porous oolitic limestone for building layered aquascapes in marine or freshwater aquariums. Provides a stable structure and limitless creative fun! Avoid introducing pests and create the aquascape of your dreams. Use with STIX™ cement to make open, gravity defying structures with lots of horizontal surfaces for attaching live corals. Use with AquaStik or CorAffix to create a base for coral frags.