Use this 2 pound bag of grey slate rocks as decorative ground filler in any fish tank, vivarium, or reptile enclosure to provide your small pet with a comfortable habitat. Thoroughly rinse the tank rocks then apply aquarium safe glue to create steps, arches, and caves for custom fairy gardens or model railways. Due to the natural growth form, each slate stone will measure no more than 0.25-inch to ensure you have a wide variety of shapes and sizes to choose from.