What Is The Difference Between Filter Sand And River Sand

20091210for most fish that pic at the substrate, sand is actually best or go the opposite direction and use really big river rock because gravel can get stuck in a fishs throator filter feeders, sand is vital have mollies that love sucking up and spitting out the sand with no ill effects or concerns, corydoras that love sifting through the sand to find yummy microorganisms, and a dragon.