Beautiful natural black color that makes any fish, snail or décor pop in a planted fish tank Great for sand digging fish loaches, goldfish, cory catfish, cichlids etc Optimal for freshwater plants to root firmly, but is easy to clean Provides ample surface area for beneficial bacteria to grow Can also be used for a Paludarium, Terrarium, Vivarium or Riparium! This Black Aquarium Substrate is perfect for aquascaping to make any plant or fish pop against a dark background. The grains are round and smooth, optimal for sensitive sand sifting fish such as Corydoras and Loaches. Many carpeting plants prefer a finer substrate to attach their roots to, allowing them to grow quickly and healthy. The sand is composed of silica with no added dyes, colors or treatments. There may be some harmless residue, I recommend rinsing several times before adding it to your aquarium. I've personally used this sand for many years with great success in my fish tanks. Mix the sand with gravel, pebbles, rocks and other decor to build a gorgeous fishtank. 1lb per gallon of tank volume will cover the bottom will ~1" of sand Planning for a deeper substrate? Simply multiply the weight needed for your tank by the depth (in inches) of substrate you'd like.