Otolith;4680311; said:You are good to go so long as they aren't crumbly (alter your pH) or glittery (metals in them). Putting some straight vinegar on them and if it foams then discard as those will alter your water.
DMD123;4680283; said:I'm not making fun of or picking - just an observation.
Its funny how rocks for $3 a pound at the fish store we dont question but rocks from the great outdoors we do. In nature fish are exposed to all kinds of items and they thrive.
I use rocks from the outdoors in my tanks and like the others have said clean/boil them and you will not have problems.