I use black diamond blasting and it doesn't cut or seem to bother my goldfish's mouths, and they are always sifting through it. I have some friends that use it in their African cichlid tanks too without problems.
I do think the darker substrates make fish colors pop better. It certainly does make my cherry shrimp look brighter.
Did it seem sharp? Was it hard to wash? Im starting to think Im going to pick up 50# tomorrow...what was the grain size like?
Thanks everyone
