depends on where the rocks are from and their history ... if these came with the tank you bought, it would probably be wise to soak them in saltwater for a couple of weeks to leach out any dead crud in their - so a search for "cooking your rock" - you really don't cook it, but, store it in a dark environment in water to encourage the bacteria to process the crud out ... it is an easy way to cut down on problems later on in your tank.
