Well, I heard this insane theory the other day about how you can't have any kind of black sand in your aquarium ( Flourite bacl, Tahitan Moon Sand) with bottom dwellers. People have said it contains sand with sharper edges and can be harmful to any bottom dweller ( Pleco. Otto, Cory catfish). Is this true, I have heard many people say it is fine, and they do it, and then I hear people say don't because it might hurt them. Can anyone tell me the truth, I think it isn't true but still won't to know what other people think...