Hi all, quick question regarding cory's. i know they prefer to be kept on sand but can i keep corries on Black unipack gravel and akadama. My 240L tank has 'islands' with akadama and then the foreground is B.Gravel. will they be ok on this substrate. My thinking was that akadama is soft anyway and it only gets softer! however will their nuzzling (sp?) cause cloudiness in the water. cheers.