Rocks From A River For Fish Tank?

[caboose_122]

Hi, my question is will rocks from a river be ok to put into a freshwater tropical aquaruim? what are the saftey procautions? i would like to add more hiding places for my fish and make the tank look more natural, also my swordtails are haveing babys soon and i would like to put hiding places for the fry.

 

[smurfyy_2k3]

i wouldnt use sedimentary rocks and i would boil and metamorphic or igneous rocks you use