CeramicNature aquarium laying house  The cavity is handmade of ceramic and they are 100% safe for humans, animals and nature. A layer house is a hiding place used by several species of fish to lay their eggs and/or raise their young. Of course you can also use it as decoration.  Specifications: Gender: unisex Colour: red Material: ceramics L-numbers: up to 10 cm (L002, L015, L046, L104, L129, L340, L400, L411, etc.)  Dimensions: 15 x 5 x 4.6 cm (LxWxH)