It certainly wouldn't harm anything. Sand is a great substrate! It looks more natural than the colored rocks, and burrowing creatures and bottom feeders like to rabble around in it. I imagine loaches, cories, and gobies love it!m Be careful what kind you get though! Don;t buy the stuff for marine tanks as that is crushed aragonite and it will raise your tanks PH too high for your fish. Also be sure to rinse thoroughly and turn of your filter so that the impellar or motor does not become scratched or damaged!(Personal experience your impeller becomes horribly loud and annoying)
