Glazed Ceramic Tile?

Thats an interesting idea. Im not sure that it would be advised, however. I once made a ceramic ornament and glazed it with a food safe glaze. didn't seem to harm the fish, but the glaze slowly broke down and im not sure what that does to the water. Floor tiles wont be glazed with a food safe glaze and probably will have industrial chemicals of some sort on them from the manufacturing process. Maybe someone else has experience with it? Let us know how it works if you do it.

From my knowledge (taking ceramics in school), glaze has a handful of different chemicals in there. Copper, lead (in some instances), and much more stuff. I'd ask the ceramics company and ask them whats inside the glaze.