Nic;1543013; said:so does this mean that a real fine 000 sand blasting sand could be used..... its a silica sand and it is the finest grade..
I don't see why not unless its really sharp. I think even ingesting it isn't bad for the fish, they can apparently just get rid of it, at least saltwater fish can.
In another article it talked about how sponges are made from the same chemical make up (silicon dioxide) and lots of fish eat sponge from time to time and it didn't prove to be harmful.
So I don't see why you couldn't.