Finally decided to opt for fine smooth, lime-free gravel - 1 to 3mm. My corys should like that. Only problem is I have searched and searched for a supplier! Dumb probably, because I did see some somewhere the other day and did not add it to my favourites! Anyone can help? Lots of gravels out there, but can't find one that specificallt mentions corys, and I don't want to use sand :?