Penn Plax Aquatic 2 Piece Granite Stone Hideaway Ornament Penn Plax Aquatic 2 Piece Granite Stone Hideaway Ornament – Granite stone hideaway 2pc. Granite stone hideaway provides a safe place for your fish to go and relax. These stackable rocks provide individual territories which helps minimize aggression. Also encourages breeding. They are a particular favourite for Cichlids, who love to wander in and out of the stones apertures. Made from pure natural ground Granite and Resin, these stones are 100% toxic free and perfectly suitable for Cold water, Tropical or Marine tanks. Ideal for Cichlids and all fish. Stackable! Reduces stress.