Unocho Aquarium Rock Stone Fish Tank Rocks 5lb Natural Rocks for Aquariums Aquascaping Landscaping Model Tank Decoration Vivariums Paludarium Miniature and Fairy Garden(3"-6"-4pcs)Brand: Unocho Color: black Features: Naturally Formed and Environmentally Safe: Black Stone is a natural rock that restores the underwater world with its natural colors. It does not alter water quality, maintaining the ecological balance of the aquarium, and is safe and reliable to use. Hard Texture and Stable Tone : aquarium rocks has a hard texture, strong durability, and a deep tone that adds a calm atmosphere to aquariums, miniature landscapes,