Dano83

Can someone please give me a list of rocks that can go into fish tanks? I went to this rock place yesterday and they are selling lava rocks for 18 cents a pound. They also have a ton of other cheap rocks that I like but i'm not sure if I can put them in my tank.

Barbrella

Lava rocks should be okay. Just make sure you soak and clean them well and be certain they weren't exposed to any chemicals at this place.

When in doubt about rocks, try putting a few drops of vinegar on them. If they fizz, don't use them in your tank as they will alter your water chemistry.

sirdarksol

You should also be aware of anything that has metallic shiny bits or have something else that seems like it could leach into the water. (For example, my parents once put a rock with graphite bits into a tank, and the fish died off quickly)

COBettaCouple

I'd recommend making a list of them and checking them at wikipedia or googling them or posting them here. Some rocks, like slate tend to be good. Some rocks will decompose or leech minerals like sandstone.

Dano83

Those are the main two kinds of rocks lava & slate that I was looking at. So they are safe to put in well that's good. Thanks everyone.