Originally Posted by AngelicScars
I use river rocks I got from Hobby Lobby. They work great and I haven't had problems with my tank or fish.
Just be sure to boil them really well.
The three larger rocks in my tank are from some river... I think in Maryland given to me a decade ago from an old Science tutor. Ones black and smooth, ones sorta marbly and one is almost like a sponge, first time I put it the tank it bubbled for 10mins before it stopped XD
Smooth on the left, bubbly one sorta right middle and the inbetween one on the far right.
I don't know if this helps... the other stones are just Top Fin Glass... pebbles. And the shells are... From Marco Island from 10yrs ago hahaha