"The Penn Plax 8 pc. Deco-Replica Cave Hideaway instantly transforms aquariums into the perfect habitat for African Cichlids and other territorial fish. Molded resin ""rocks"" feature multiple holes and when stacked together create a labyrinth of nooks and crannies your fish will use and enjoy. Kit comes with 8 rocks, for many combinations of possible structures. Creating structure and hiding places in the aquarium may reduce aggression in territorial fish, especially African Cichlids. Stimulates natural behavior including courtship and breeding. Caves vary from 2.5, 3, 4, and 5-inches high. Realistic granite-textured resin. Gender: unisex."