That sand is actually really sharp and can damage their gills while sifting unfortunatelyif you're looking for black, I'm obsessed with Black Diamond blasting medium in medium grit. if you want something finer they do have have a small grit. it's at Tractor Supply Company for like $10 for a 50 pound bag... such a steal. I have it in all my tanks except one which has pool filter that I hate because it gets sucked up in the python haha!